No Agent Mulder in Hulk 2
And yes, the sequel is still a go, according to Avi Arad.
Addressing rumors that The X-Files' David Duchovny was being cast as Bruce Banner in a straight-to-DVD Hulk 2, Marvel exec Avi Arad said that’s not the case.
"Well, Marvel is going to make the second one themselves with Universal distributing it... so this will be a Marvel production outside of the Paramount distribution deal that they set up last year," according to Ain't It Cool News. "Right now, Avi is talking to various directors and writers and he intends to make a direct sequel... not a reboot. He feels that the Hulk was a bit too big, so the big green behemoth will be not so [Mighty Joe Young]. He's very excited, as always, about the Emerald A**-Kicker, and at this point there is NO recasting in place or planned."
Recently however, Eric Bana indicated that there was no movement on Hulk 2.