http://www.seibertron.com/news/view.php?id=12525 So, according to the article, at least part of the filming for the sequel is going to be done on the east coast. Reportedly. Kinda makes me wonder what they're up to, since the first movie was based in the southwest. Maybe this is only for certain portions of the movie? What they'd be up to in Philidelphia though, I have no idea.
But hey, at least we haven't heard anything from Vegas yet.