When you pick up your gold bars in Hong Kong and attempt to carry through customs back to the US please let us know how it goes...
As it happens, I visited the Toi gold museum last year in Japan where you can touch the largest bar in the world (250kg):-
http://en.wikipedia.org/wiki/Toi_gold_mine
Anyway, the gift shop sells these fake gold bars made of steel / tungsten but even though I was tempted to pick one up and stick it on the mantlepiece to throw any potential future burglar off piste, even carrying a fake through customs might ring alarm bells for a bored immigration officer looking for some action with the rubber gloves.
Wrt gold generally I'm also surprised that price action is not stronger given the possibility of EZ breakup, seizure of EUR bank accounts via capital controls in Greece, Spain, etc. If you're living in one of these nations surely you'd be making contingency plans and gold would be part of the mix.
But in light of the theoretical arbitrage which you highlight and current Chinese slowdown perhaps it signals how significant Chinese gold buying was in driving the gold price up in recent years, and now we're seeing the other side of the (gold

) coin. It tells me that Gold above $1550 will be hard to sustain, even with demand from Europe.