He could very easily have his own film- his mutation, like Wolverine's, can be symbolic of an emotional invulnerability, and his sheer size and power can be done very well if he's ever in a situation where he is helpless to save someone important to him. For all intents and purposes, he should take wolverine's role as the tragic and physically invulnerable/emotionally very vulnerable character.
He'll never get his own film, unfortunately, even though it would easily work. Here's to hoping that X4("Young X-Men") focuses on the following character developments:
-Bobby: his rise to becoming team leader for the young x-men, albeit make it a rocky one because of the bobby/rogue/kitty love triangle (where the others don't really want to follow him as team leader). [And for the Cyke fans, have Bobby realize that Cyke went thru similar hardships when he was becoming the x-men leader, and thus look up to him as a role model. Coincide Bobby's rise to leader with flashbacks of Cyclops' rise to leader.]
-Bobby/Rogue/Kitty: It would be VERY interesting to now have some students at the school be uncomfortable around the human Rogue (it would be cool to see there are mutants unacceptaing of humans, just like the humans are of them). Better yet, what if Bobby is one of those students and that he's now more attracted to Kitty instead of a human Rogue? You can feel the irony of her situation coming. And looking at Kitty's power (and her respect for Rogue, hinted at in X3), what if she won't let Bobby touch her at all because she takes Rogue's side? Ironic for Rogue that now she is physically able to be with Bobby he doesn't want to be with her emotionally, and ironic for Bobby because whereas he couldn't be in contact with Rogue, now Kitty won't let him be in contact with her either. [Just saying there's a ton of possibilities]
-Colossus: his massive size/power and physical invulnerability needs to be used to put him in a situation where he is too weak to solve it and emotionally entirely too vulnerable (doesn't have to use his sister, just something to get those themes across). And it wouldn't hurt if he actually spoke a line here and there too.
-Pyro: Neither accepted by the X-Men or the Brotherhood, he should really become a super-angry, super-violent tragic villian (and lead mutants of similar violent motivations). A badass character, but a victim of society that meets his tragic end at the hand of Iceman. Make their battle the climax, a personal one, with just Iceman and Pyro- no x-uniforms and no young x-men team (they can have their big battle somewhere in the middle of the film together).
The charchter itself works. Has alot of backround history, strong charchter and a unique one at that. Extreamly powerful yet artistic, noble and chivarious in a way. Loves his family and his old country. 
