I picked up a frame from the powder coater today, and we talked about the process of masking. Sounds like he needs to do one round of masking during the sandblasting (using something like duct tape), then remove that tape and all of the glue residue, and then apply a tape that can withstand high temperatures for the powder coating. He'll scroll around the edges of headbadges or other kinds of masking. So it can certainly be done, but just adds to the labor cost.

BTW, if you're in Massachusetts, I highly recommend this powdercoater in Plymouth, MA: Long Beach Custom Fabrications, http://www.lbcustomfab.com/. He charges $50 for a blast and a single color coat, and usually completes the job in a week or so. He's done two frames for me now, and about five for a local bike buddy. Good stuff.

Neal