Sounds like you'd be somewhat close to Race Proven Motorsports in New Castle, DE. They do a lot of LSx tuning, and aftermarket parts installs. Believe the guy that owns it can be found on most LSx car based forums by member name Fran02SS or something like that. The guy has always been very helpful on the forums. I know you probably already found a shop but if you haven't and to serve as some info for others here.
They always have tons of 5th Gens being worked on, they also helped me finish up my custom CSC build on my Monte Carlo. Then I would just ask Dale (the owner) where he recommends for body work. They are a great group of people. Also right next to them is a nice father-son detailing shop called Rivers Edge, they might have a better idea for body work if Dale doesn't know.
*edit* I didn't see when the first post actually was, but still helpful to know I guess. haha