Does anyone know of a gunsmith that can do a barrel swap and headspace a M1 Garand?

TTI in Ashland use to and may still. Rick Carlton owns the business and was (and probably still is) a M1 enthusiast.

Found 'Guns Gear & Ammo' out of Cascade, VA at the April Hampton show. They took the rifle back to their shop, swapped the barrel and finished the chamber for proper headspace, test fired, and sent the rifle back within 2 weeks. Work looks very well done and no marks on the receiver or barrel finish.