I've sold a few commissioned builds and bodies/necks. The pieces where I make the most money is on the parts but I'm still not at a break even point when I take into account the investment in tooling. tooling wear and tear and supplies.
I'm just happy that I can eventually break even and to have happy customers.
The completed builds don't bring in as much money. The last one I sold was a very nice piece and it sold for $750.00, after all fees and whatnot. The guy paid around $850.00. It was a thinline Tele with binding and nice MOP inlays. I hope that the two I'm working on now will bring in a little more. Fact is, if you're unknown or a small shop, completed build don't make money. I have sold others for more than that, obviously, but its a tough market and you have to be very patient.
For me, repair work, whether it be guitars or amps, its too much time and is not worthwhile IMO. You have to meet the person, they want to chat, you do the repair, then the customer wants to exchange emails with you, you finish the work, meet the person again, they'll want to chat some more... not worth it. I'll only do repair if someone absolutely wants me to do the work. These days, I just say no unless the person is in a bad situation.