While having a US License is a great thing and should be actively encouraged the inability for the FCC to tag an international address for a license holder is an issue. [ Didn't the 9-11 bombers use "remailer" and non-actual but technically valid addresses for their Pilot's licenses? ] This is something that I think that the ARRL should be attempting to resolve as a matter of urgency.
I have looked for the places that do online testing and they all require a valid USA form of ID. I have the FCC number!
The requirement of a domestic address is a common requirement in many countries. For my VE2KVU and 9A5KVU licenses, I had to make arrangements for a suitable address with my paperwork. It wasn't hard. A public service announcement is perhaps in order for folks reading this thread: Remember, if you get a license in another country, then generally when operating in that country, you have to sign with the call associated with that license and operate within its privileges. For example, if you held a Full license in the UK as G9XYX, and took a US tech test for fun, being assigned the call WX1YZA, then when in areas under FCC juristiction, you have to sign as WX1YZA and operate within Tech privileges. You would no longer be authorized via CEPT to sign as W1/G9XYZ or use the Extra privileges via treaty.