I have fitted E27 bulbs to US sockets several times without much trouble. They do leave a lot of thread exposed, but not more than some old Austrian sockets.
I have seen some reference to B22 being used in Europe. If so where?
Greece and Spain seem to use B22. In case of Greece that's even weirder since _all_ of the Gear I've seen used seems to have been German, mostly Siemens. The panels were a mix of Diazed and DIN rail gear, almost exclusively Siemens Germany. Sockets were typical German/Austrian/... Schuko, including the mounting with claws (one at my hotel room pulled out of the wall, that's why I know), wiring is done with either flex conduit (PVC) or German/Austrian only flat NYIF style cable. The old switches look somewhat British, the new ones definitely Continental.
