Whilst this could be a really cool idea I think it would be hard to get too many people together due to how this forum has a very wide international audience.
Whilst many are in various parts of the US, I'm in Sweden myself which isn't all that far from Germany, though far enough that I doubt I'd be able to attend an event like this.
That said, I will be heading for Berlin in August to attend Eurofurence so if anyone else is going there, do let me know!