I started one in Seattle three and a half years ago. I handed it off to someone else a year ago, but I was getting ~150 people per event, and the meetup list has grown to 2000.
All you gotta do is pick a time, a place, and get the word out. Then boom! Done. :)
Organize one! I'm in north San Diego county and for a little while we were doing them up here occasionally. I just poked the SD list and found enough interest. If you did one in South OC I'd show up.
Sure, I'd much prefer 1-1 sessions rather than a group meetup. Don't get me wrong -- the meetups are great, and it's fun to meet new people. But you don't get to dig into much of anything.
I'm in SD (live in PtLoma, work downtown) and am down for a cup of coffee or lunch. Can do during the week if it's close to downtown, otherwise I'm sure we can figure something out. Email is in my profile.