Yeah, I see a lot of people were thinking the same thing as me. A whole story about Caretaker be awesome. It could show more about the town and the 1000 souls. It could end with showing Mephisto chase him on his own demonic horse and we see how he outruns the devil. Show Mephisto didn't just stand there. Marvels been rolling out the animated movies and I think the story of Carter Slade/Caretaker would work really well as an an animaited movie.
Ever since MSJ first showed the picture of the two Ghostriders riding together I thought his character look awesome. Talk about an improvement on design! Its up there with the improvement the hellcycle got.
At first I was thinking a live action would be cool (and it would), but I think an animation could get made more realistically. The idea for an HBO series is cool too. MSJ's got the in with The Preacher series, so if that did well he could pitch them this. Each season could be about another Ghostrider. After they did Caretaker's season they could do Ghostrider 2099. I think that character's story would be awesome to see too. Or an animation of that would rock too.
Or they could make one movie like the animatrix and tell a little about all the different Ghostriders, Zarathos origin, Vengeance, even some extra scenes that take place inbetween the live action movies. We could see that Blackheart is alive and more badass then befor in true demonic comic book form.
Another animated movie Marvel could do like the animatrix is a "What if ...." They could animated all the scenes fans wanted to see in the Marvel movies and didn't. Along with classic what if moments.