My neighbor helped me with my control room wall. It's not a huge deal. It's brass tacks, costing me maybe...$3-4000 including labor/materials when all said and done.
My example's rather rough as I just wanted a wall to separate noise from my monitors. Nothing soundproof so I won't share. Granted, if curious, I'm happy to show you receipts, photos, etc.
However, regarding his own room, he's built out his own studio control room and tracking booth in his rehearsal room which you can check out here. It's really impressive, and it's sound is tight. I ask to show my friends every chance I get: MySpace UK
That's why I hired him.
If you ask his help, just tell him Alex sent you if you ask so I know I'm helping a brotha' out. I can probably get a hands on show and tell if interested.