I'd like Gerald Wallace at the 3, Anthony Randolph at 4 and Marcus Thorton at 2.
Gerald Wallace is one of the top Defensive SFs in the game, I believe. His contract is manageable and he's only 27. Plus, he's one of the very few that gives Lebron trouble.
Anthony Randolph? KG - Like. Needs to gain some pounds, though. He's very young at 21 and has Plenty of room to develop.
Marcus Thorton impressed me over the last few months in NOH. Really nice shooter that can fill it up. A little short for a SG, but I like him.
If this is down the road in say 2012, then I'd say this is doable. G Wallace and Randolph along with Perk makes for a very Scary Defensive Frontline.
Now the Dream SF is of course that man named Kevin from OKC. He is very raw defensively, but Boy he is surely showing flashes of greatness even in that area. The defense he played on Kobe in their series has caught my eye.