A Dolphins beat writer claims they have 14 million in cap space for 2012. That might be enough to get Peyton, but him alone does not make that team very competitive.
http://blogs.sun-sentinel.com/sports_football_dolphins/2012/02/nfl-salary-cap-crunching-the-2012-numbers.html
According to John Clayton, the 49ers have 39 million in capspace including 2011 rollover, but not including Ahmad Brooks' new deal (8 mill cap hit this year iirc). Plenty of space to get Manning, Wayne, and more. They could re-sign Alex Smith as a backup too. SF is a much better spot as they have a top 5 defense already (need to re-sign or replace Carlos Rodgers though), an excellent TE in VD, a pretty good run game, and a good O-line. They could use some WR help, but if Wayne comes along, having Crabtree as a #2 would probably work out. Seems like a much more ideal spot to me.
http://espn.go.com/nfl/story/_/id/7570116/nfl-plenty-cap-room-improve
How the F do the 9er's have 39 million in Cap Space, don't they have like $400 million tied up in thier secondary? I just don't understand how some of these teams have the room they do. Look at the Eagles how do they even have ten bucks in Cap Space with the roster they have? It's crazy.