Garage/Garage Apt. building help

I'm looking to build out a new garage with an apartment above it and am looking for recs on a builder (in the Baton Rouge area). I just want to get it to the rough-in stage and do the rest myself. The contractor that built my house will do it, but he's a bigger outfit and his price reflects that. I'm looking for a smaller company, or even individual who can help get it where I want it (and hopefully for a better price than the bigger guy). Any help/thoughts/recommendations are much appreciated