I read the literature from pacific states galvanizing here are the problems. The frame needs to be easy to drain you need large holes in the bottom bracket and head tubes. The bigest problem would be the seat stays. The frame needs to be welded any brass would disolve in the zinc bath. The frame needs to be well cleaned this includes welding flux inside the tubes. The zinc penatrates .1 mm into the tubes making that part of the tube weaker so very thin tubes would be risky. They put a type of paint on the parts you don't want to plate this would include the inside of the head tube where the headset goes and the inside of the bottom bracket where it is threaded. Then you would need to ream and face the head tube and cut the bottom threads after it has been galvanized. The outer part of the zinc is to hard to cut threads in. All this may be more trouble than it is worth. Thorn seals up all their bike tubing find out more at http://www.sjscycles.com You might consider electroless nickel or electroless silver plating or even electroless gold plating.