To give this some resolution: It seems like we do not have enough traction for a bigger meeting in a particular location in Europe. One way to bring the Europeans together is to promote some of the UK/London meetings on a bigger scale to invite traveling from abroad. For small scale meet-ups there are some cities or regions with a few LW-readers in them, that can meet informally.
There are readers on this blog from all over the world - many of them spread out over Europe. How many of you would be interested in a European meetup of LW readers?
We do not have big clusters like Silicon Valley, but we have low cost airlines, and lots of interesting places.
If interested please comment.