We recently had a vintage table base sandblasted and powdercoated at Melrose Metal Finishing and despite our desire to keep this great resource a secret, it's too good not to share with all of you.
Melrose has been around since 1968 and mainly does commercial work, but they were happy to take on our small project, and did a great job for a very reasonable price. They are hands down one of the best vendors we've ever worked with - friendly, quick, and completely on top of things. They gave us a quote from pictures we e-mailed them and stuck to it, something we always appreciate.
While Melrose specializes in metal they also do "wet painting" and so can cover your wood and fiberglass needs too. Yes, the location is a little out of the way and industrial (out by the Oakland Airport/Coliseum,) and their hours are early (M-Th 7:00 a.m. to 3:30 p.m. and Friday's 6:00 a.m. to 2:30 p.m) but we will definitely be recommending them to our friends and returning there the next time we need something refinished.