It has been said Norway is the biggest market for Tesla outside of the US. (Or was it in Europe? Canada might be bigger.)
Last I heard there were around 400 reservations here for the Model S. That's 1 Model S for about every 12 500 inhabitants. The US has 1 Model S reservation for about every 26 000 inhabitants.
This is before we know pretty much anything about European pricing, CHAdeMO specs, three phase specs, if we'll get superchargers, etc. And we have just one store, where there's been one Model S beta at one time for under a week. No one has had test rides or test drives.
I think once Tesla actually starts focusing on Europe, we'll see reservations increase rapidly.