I am just curious as to what answer [if any] ever came out of this - whether the mac address change worked, or if it was actually possible.

I have a US n800 that I use in the UK and I recently ran in to an issue with a network running wifi channel 13 while visiting Spain. We ended up changing the router to channel 10.

FYI, my language and locale are and always have been set as UK.

Cheers.