I don't have an answer for you, but I essentially have the same question.
Our Tampa FMPug has been broadcast over gotomeeting, and we sometimes get more virtual attendees from outside the area than inside the Tampa region. We're considering dropping "Tampa" from the name and just calling it what it is, a virtual group.
We like the way this is going, and where it's heading, but we're still a pretty small group, too. I'll be interested to see others' ideas. If we could grow our group, too, the more, the merrier.
If yours is an open group, could I attend, or perhaps even contribute? Would you like to attend ours (or perhaps even contribute)? We meet the second Thursday of each month, at 6 PM. If you'll contact me backchannel, I'll add you to our email list. (Actually, you or anyone else, for that matter. )
One obvious way to grow our groups would be to attend one another's meetings, or even have joint meetings.
I 'attended' Tampa's last meet, and I loved the format.
Although I enjoy my local group (nyfmp) for the social aspects (can't beat dinner out in NYC), I found I get more out of the presentations if virtual. You can't beat a clear and close screen! I also like that the text chats for questions and discussion avoid interrupting the presenter. With both text and audio, you can still have the lively post-presenation banter, although technologically squelched a bit.
I hope to 'drag along' some of my local members by announcing the next Tampa meet on our google group. And don't forget Twitter, Linked-In, Meet-up and FB for promoting your v-meeting. Oh, and here on FMC.