In rough order:
Suggest you check out the Harpeth Valley bike club site for local shops. Maybe someone you contact there can give you a firm recommendation.
I stopped by Bicycle Pedlar (sp?) back when they were Allanti. (They were advertising Gunnar bikes, and I was thinking about getting a custom tourer.) I don't get up there often, so I was surprised when they had moved a year or so later. Staff was interested, pleasant, and seemed knowledgeable during our chat, but I didn't actually buy anything, so I can't give you a firm recommendation.
Also, REI has a store in Brentwood. The bike department wrenches usually have something to do, for whatever that's worth.
Do a google search for "Nashville bike shops."