Hmm, not the sort of problem I'd face as there are no residental electrical inspections here, but I'd certainly complain to the appopriate State or County having jurisdiction, quoting the relevant NEC rules etc.
If I was desparate to get an approval certificate I think I'd do it the inspector's way then go back and bond the pipe after he'd left. It seems incredible that an official of the local govt. cannot be held responsible for his orders.
As Steve said, what about the ground wire to the furnace controls? Trying to isolate the gas piping seems futile (as well as potentially dangeroous).
There's no piped gas around here outside the couple of larger towns, but bottled LPG and oil-fired heating are common. Now that I'm leaving, I've just about convinced the local plumber that I need to bond these lines, and to tell me if he's going to use plastic couplings so I can bring along enough clamps.
Bonding of gas (& water) lines is conspicuous by its absence in many houses around this area.
