A quick front-page link for Greg Cowan's excellent look on how long it takes teams to rebuild.
Greg and I talked a lot about this piece behind the scenes, and I'm very jealous of him that he came up with the idea. I kept hoping he'd forget about it so I could steal it from him.
It's a great piece, and worth a read. It's pretty clear that a team can reload within 2 to 3 years after bottoming out in the NFL. That's pretty short.