Jackman's apparently on a 6,000 calorie/day intake to become more muscular to fit Aronofsky's vision of the character.
Personally, if they aren't going to tie this to the existing continuity and their plan is to create a separate, stand alone thing (as everything I've read on the subject leads me to believe,) I'd rather they just recast the role. Jackman's version of the X-Men universe is all fucked up now anyway, and it needs to be buried. There is no joy in the current X-men film franchise anymore. They became increasingly morose and lost any spirit, charm or wit as they went along. The first one was fairly decent as a standalone, but 2 and 3 were both pretty horrible and the Wolverine movie was godawful.
As for these movies being made in the same continuity with the Iron Man films, you can pretty much forget about that ever happening. Fox has rights of first refusal on X-men, Fantastic Four and a bunch of others, while Sony has rights of first refusal on Spider-Man. As has been explained earlier in this thread, it basically means that if a studio commits to making another movie utilizing those characters, they get to keep them. I could see Ghost Rider, Daredevil, Elektra and some others eventually reverting back to Marvel in time, but X-Men, FF and Spidey aren't going anywhere.
Also, I don't really think it matters that these characters exist in the same universe. I mean, as a long time comic fan, it's cool to see them interact with one another, but it won't be very common. Disney won't really make that much more money on the Avengers movie than they will on an Iron Man, Thor or Cap movie. All it will end up doing is costing more to make, which will eventually lead to sequels suffering budget restrictions and other logistical hamperings and so forth.