Well, here goes. My plan for an Avengers movie franchise:
This plan would, in fact, begin with the individual films for four of the characters. They would be:
Captain America: Set in WWII, the film would depict a young Steve Rodgers becoming America's first superhuman soldier, Captain America. Bucky would be introduced as Steve's slightly younger friend who serves as his feild handler once he finds out that Steve is Captains America. The plot would involve Cap's early exploits, and him facing off against Germany's top assasin, The Red Skull.
Visually and stylistically, I would want to capture the look and feel of an old pulp fiction novel. While it shouldn't have the large amounts of CGI, it should look like Sky Captain and the World of Tomorrow. Cap's costume should really look like his WWII costume from The Ultimates. Possibly changing the mask slightly by ditching the helmet and making the leather mask blue with an A on it. However, Cap's classic costume would not go unseen. For PR purposes, he would wear it at major events. He would apear on recruitment posters, and there would be one scene during a USO show where he's wearing it. However, on official missions, he would wear the more practical Ultimated WWII look.
The Red Skull, similarly, would be changed in terms of apearance to suit both practicality and the style of the film. His mask would be a red metal helmet with a skull design over the face. His weapon of choice would be a Gladius, a short sword origionally from Rome designed for close quarters combat and quick, spine severing kills. However, while he would be an acomplished hand to hand combatant, he would not pose a physical threat to Cap. Cap, being superhuman, would thus be superior to the Skull in close quarters combat. This serves as a point of anger to the Skull, who is an egotist with a superiority complex. He refuses to be anyone's inferior. So, he is much more Cap's intelectual challenge.
Bucky would be about sixteen or seventeen. He's Steve's fellow soldier and best friend. Not a sidekick, really. More like a drinking buddy who, by chance, ends up being the guy who keep's track of Cap in the feild. He would not have a costume, although there would be a scene with him wearing a blue shirt and red work gloves similar to his costume.
Casting wise, I would want Cap to be in his early 20s, Bucky to be in his late teens, and The Red Skull somewhere in his 30s.
Thor: The story would begin with Donald Blake, a physician in Norway, discovering that he is in fact the Asgardian warrior prince known as Thor in human form after an old wooden cane comes into his possesion. When he touches the cane, he is flooded with memories and information of his true identity. However, before he can do anything about it, his ravings about godhood land him a nice cozy cell in an insane asylum. Several months later, while wandering the halls, he is able to steal the cane from the patient prperty locker where it is being kept. Before the security gaurds can stop him, he strikes the cane against the ground. The cane transforms into a nortic war hammer, and Blake buts on about 20 pounds of muscle, grows long blond hair and a beard, and his clothes are replaced by what resempled a mix of modern clothing and Viking armor. He escapes from the asylum, and becomes Norway's self proclaimed savior. He would use his abilities to preform acts of heroism, while using the humility he learned as a human and the inherent wisdom of Asgard to help lead humanity away from their aparnt path of destruction.
However, through the film, we soon meet Loki, who has been living on Earth for centuries with his children. He hunts down Thor and tries to kill him as part of their centuries old rivalry which has, on Loki's part, turned into a very warped obsession. After Thor is dead, Loki's plan is to create chaos on Earth in his own name and draw power from it.
As you can see, this version of Thor is a mix of 161 and Ultimate. This is mainly because I don't think all the elements of either as they were would work in a film. Thor's personality would remain mostly unchanged, and would speak in a manner more in tune with 616 than Ultimate. Thor's apearence through the film would be much akin to his Ultimate look. Loki and his children, for the most part, would apear in human form and in plain clothes. However, in the final battle between Thor and Loki's brood, each flash of lightning created by Thor's storms would reveal their true forms, showing them looking quite similar to the 616 versions (although Thor's costume would be much more armored).
The intended feel of the film would be one comperable to Highlander (I/E, a mythiological tale set in a modern setting), albiet on a somewhat larger scale.
Iron Man: The film would start with Tony Stark, billionare scientist and industrialist, going to Hong Kong on a buisness venture. While there, he is kidnapped by an underground revolutionary movement who want Stark to build them weapons to use against the Chinese government. The movement is led by a man called only The Mandarin, a man decended from nobility who, had the communists never taken control of the country, would be a very powerful figure in China today. His plan is to overthrow the government and declare himself Mandarin of a new Chinese empire. After spending several weeks captures, Stark is able to excape with the help of a fellow captured scientist. Tony quickly goes to the Chinese government to warn them of the impending coup, but even with the information he gives them, he knows they won't stand a chance against the movement's weapons, and knows he would not have time to supply the government with any of their own. So, using a prototype exo armor, he goes after the Mandarin himself.
The main story of the film is Tony's transition from a spoiled, selfish pretty boy into someone who genuenly cares about helping others. His inventions give the Mandarin the ability to hurt people, so he takes on the responsability of stopping him.
In terms of apearence, Iron Man would look very much like the Ultimate armor. The Mandarin would not wear robes or anything like that, and would instead were fine suits or other expensive garments. His rings would be based off of Stark's designs.
Nick Fury: The United Nations puts together S.H.E.I.L.D., and international peace keeping agency that responds to the U.N. and only to the U.N. It owes aleigence to no one nation in particular. The feild director is Nick Fury, an old amercian war vet with a very head on aproach to international terrorism. When his old rival Baron Wolfgang Von Strucker, leader or the terrorist organization known as Hydra, resurfaces, Fury takes up the task of going after him personally.
The basic idea of this movie is James Bond with a blue collar worker from Brooklyne's aditude. It would be more or less the same as the comics, although it would follow no specific storyline.
The Avengers: Acting as a sequel to all four films, the movie finds Nick Fury charged with the task of putting together a team to deal with threats beyond the scope of normal agents. He puts together The Avengers, a group of agents both super powered and normal. The group is rounded off when Captain America is unthawed.
The film would follow Mark Millar's Ultimates very closely due to it's cinimatic feel making it perfect for a direct film adaptation. However, many elements of 616 continuity would be used. Bucky would have died on his and Cap's final mission. The Hulk would not be shown to be sadistic as he was in Ultimates, and in fact would not talk at all. He would apear more as a rabid animal, completely out of control and running on instinct and rage. For the purpose of time, there would be a few early mission scenes with the team dealing with relatively mundain threats. Hawkeye and Black Widow would be introduced in this film instead of the sequel, and there would be a few Cap/Hawkeye moments remeniscent of the Busiek/Perez Avengers. The movie would still contain the whole "Hank going crazy and atacking Jan" thing, which would serve as a cliffhanger ending for the film. The sequel would contain the plot of the second arc, and many 616 elements and elements from that arc mixed together.