Kevin, I feel your pain. I've tried to quit contracting more than once, but always came back out of necessity (the money). I can think of 2 ways to beat the burn out: delegate and become the office boss, or close the doors, take a job with benefits and do some side work (with an assistant so you can get things done).
One door installer I knew had a shop with employees while he concentrated on the outside work. When he got hurt and had to go inside, his business tripled. You know, part time in a hardware store (or some retail) will leave you some side time.
You could also analyze your business and cut it into separate functions. Pick one or two of the best functions for you and farm out the others. You know, Chip Foose doesn't paint his own cars and neither did Boyd. (I know the guy that paints the "Overhaulin'" cars and he's good. He also doesn't mind delegating and/or working 24hrs straight.)
You just can't do it all and do it by yourself. Ask me how I know.
BTW, I started a business model where all I did was structural tub welding repair. I wouldn't use any fillers except the lead I put over butt welds. I figured the painter was the one to straighten out the panels and be responsible for the final outcome. What happened was I couldn't physically do the work. You're welcome to my model and any advice that you may want to consider. To make it really attractive, you'll need a Celette or equal. You'll need a sheet metal fabricator as well. Any monocoque sports car was eligible for a quote.