If people are seriously talking about Cherry/GMK tours in germany, I will be based there next year, and would be happy to do the legwork of organizing stuff.
I was just doing a bit of research, looks like Cherry is in Auerbach, and GMK is in Wernberg-Köblitz, which are literally 45 minutes apart, so it would be really easy to make a day of!
They're also both about 2 hours from München, which is basically the biggest tourist destination in Germany, so the whole gathering could be a great two-day thing.