re: Spider-Man 4: May 6th, 2011
From what I understand, Fox (as well as Cameron) want the movie to open during Memorial Day Weekend of '09. As of right now, that date is pretty much locked.
Jon, scripting began on Spidey 4 well into post-production on Spidey 3 (they hired David Keopp). The studio is also quietly looking to replace both Tobey Maguire and Kirsten Dunst in the lead roles. Everyone else who appeared (and didn't die) in the first three movies will be back for #4 (namely Bryce Howard, JK Simmons, Rosemary Harris, and Elizabeth Banks).
Joseph Gordon-Levitt, Jake Gyllenhaal, and an unnamed third actor have been talked about as possible replacements for Maguire, while Mandy Moore and several other actresses have been mentioned as replacements for Dunst. The studio wants to ink the new players to three-picture deals, something they didn't do with Maguire and Dunst. The same goes for the next director, should Raimi opt not to return.
If Maguire were to return he'd command between $20-$30 million. He was paid $17 mil and $19 mil respectively for Spidey 2 and 3. Raimi has been eyeing New Line's "The Hobbit", as well as another "Evil Dead" movie, and seems to want to take a break from Spidey.
This could all be moot, but Sony does want a new movie in theaters for the summer of '09. Their best case scenario has a Spidey movie coming out every 2-3 years.
Bringing Raimi, Maguire, and Dunst back would play havoc on the budget, as it did with Spidey 3. Yes, the studio would love them to return, but its not really cost effective at this point and could be a good time to hand the franchise over to new blood.