Earlier quoted context omitted.
If you are running Gmail through google apps for enterprises, then you do have customer support options. Of course, then you also pay.
E-mail support is only for "select administrative issues", and phone support is only for reporting "a service unusable issue caused by a Google server error"[1]. It doesn't sound like the GP's issue would fall into either of those categories. [1]: http://www.google.com/support/a/bin/answer.py?hl=en&answ...
Instead, the silence on their troubleshooting forums is deafening. It's as if the engineers just don't care about fixing it, despite what would happen in the real world if a Google Apps sales rep came to our company to do a real evaluation... I suspect they would be laughed out of the room once they admitted they couldn't handle meeting invites with more than a handful of attendees.