Hmm... maybe surnames on girls is uniquely American? After all, Taylor is a top 100 BOYS name is britain. But, also, it was a practice in the south long before the trend hit the rest of the country, was it not? Girls named Sullivan and... other surnames. Yeah, I really don't know much about it, aside from that it happened.
Would "hippie" names be uniquely American? I really don't know much about the 60s in Britain and Europe. Did any other county have Rainbows and Moonflower?
Thats all I have for now - but I will be back! Maybe. This is fun :-)