There was a lot of debate over whether we should do the first European SUS in London or Berlin. Both cities are great and each has its benefits.
We have some awesome YC alum in London (and the YC community there is growing), and we're excited that they'll be joining us in July. We'd love to do something in Berlin as well.
IMO the best way for YC to do something to start with in Germany would be to get involved in CCC/31c3. (CCC is a weird combination of IEEE/ACM and hackerspaces, and huge in Germany)
A "how to turn your project into a company? should you, and why?" talk by YC (ideally, with European YC company founders, ideally in the product spaces most interesting to CCC hackers) would be awesome. The downside is it's 27-30 DEC in Hamburg.
In principle there isn't any reason a YC partner couldn't just give a talk if they wanted to. For example Harj did a session at HackerNews London just over two years ago [1]. I don't recall it being an official 'YC Event', just one of the partners who happened to be in the UK at the time and was willing to do it.
However, looking at the current list of YC partners [2], I don't see many that might have ties to Europe, such that they'd be visiting much (never mind the imposition of giving up family/holiday time to give a 'work' talk).
Both are a great choice, both are easy enough to travel to. It's awesome that this is happening. Berlin would draw more people from Eastern Europe, IMHO.
Here in Vienna, we'll have an event with quite a few YC alumni on May 29: http://foundertalks.org
We do not have the means yet to make it free, however. We basically started this a few weeks ago, because we felt that something like startup school is missing in Central Europe. I guess you must have felt the same :-)
EDIT:
P.S.: After our event, I'd be happy to give you some feedback regarding what kind of questions/interestes/etc. European founders voice in such a setting. It's an awesome experiment, I'm really looking forward to it.
There are at least 4 YC alumni in Berlin off the top of my head. Get in touch if you guys are looking for some on-the-ground support at some point in the future.
We have some awesome YC alum in London (and the YC community there is growing), and we're excited that they'll be joining us in July. We'd love to do something in Berlin as well.