Sure, at this point it seems like a no-go.
But a few things I'd like to point out.
-Since when do supposed "Insiders" who leak info talk like PR guys?
-Of course there is no announced sequel when they have no idea how their slate of movies will do throughout 2011 not to mention they've pretty much maxed out their slate.
-They were fruitful (DBZ) you can go to BOM to see that. If you count fruitful as only Iron Man / Batman / Spidey numbers. Then I pity you. There's a difference between a smashing success and an under-performer.
-DVD's aren't even out where many movies were given their "second-wind" yet. (See: Hellboy, HULK '03)
It's premature to start singing praise to the Gods that a sequel is in the works but it's also to late to start screaming "No way, not ever." We can speculate but as Obi-ron said, it's all speculation until it comes straight from the Horses mouth, which it won't until AFTER the Avengers on what their plans for the future are.
Heck, it could not get a sequel, and Iron Man 2 could be cancelled / moved back. (I doubt the former,) due to Faveru's dislike of no-prep time. Either that, or it could be a crappy film even. Why people on these boards pretend things are definitively going to be one way or not is beyond me.
It's the waiting game from here on out. If we get a solo-Hulk it won't be until 2012 or after. So just sit back and enjoy the onslaught of comic book movies.