I ended up getting Sal to do the concrete on mine and I subbed out the rest (most of it to John's Lumber, but I don't think they offer the actual construction anymore). If you bring John's in a rough plan, they will spec out what you need for everything. Saved more than $10k over what Miller Garages wanted. I know Miller is pretty big and only does garages, and I have heard they are pretty good at it (nothing specific though).