Although I am a native Iowan, (and my brother lives in Ames), unfortunately, I am not aware of anyone. However, if you chemically strip the frame first and just ask a local blaster to do a quick, light once over, you should be OK. Where blasters get into trouble is when they try to take all of the paint off quickly, like they do on a chisel plow or manure spreader. I never bead or otherwise blast a frame unless its been stripped first....it takes too long and is too hard on the bike IMO. Ask them to use glass bead or 80 grit aluminum oxide under low pressure.

Dave

PS: If you are ever up in the Cities, let me know and I'll take care of it for you.