I really think that only the Lakers, Clippers, Hawks, and the Bobcats have a shot of landing both of these guys.
Lakers would have to amnesty Kobe in order to make room for CP3 (not gonna happen)
Clippers would need a sign and trade with Lakers in order to make room for Howard trading Bledsoe & Griffin or Jordan for Howard (this is feasible, but I don't see the Lakers trading Howard to their in-town rivals)
Hawks could make room, but would literally be cutting everyone on their roster and would have no chance to compete next year
Bobcats would have to trade expiring contract Ben Gordon, and Amnesty Tyrus Thomas.
I think the Bobcats are in the best financial position in the league to make it happen... odds are it won't though.
The Rockets could also make space for both guys. Off the looks of it they have $38 million in committed money, with the likes of Garcia, Delfino, Brooks, and a few other low earners. Those three guys if the Rockets take their team option would combine for $12 million. But they could cut them and free up some money. The other way they can make room for them is to trade Asik and Lin, both of whom will have quite a number of suitors.
For the Rockets if they can trade Asik and Lin, and in turn sign D12 and CP3, then that would be an excellent swap. Would the Lakers and Clippers be interested in a trade and sign deal?