Great stuff in this thread.
My vote is for once a year, complimented with "limited seating" events throughout the rest of the year. I'm tellin ya Trey, this event has the potential to become enourmous. I've taken part in similar events for a different car that started 8 years ago... it started with under a 100 cars showing up, and last year they drew almost 800. Now its a totally different demographic and totally different type of event, but the idea is the same. Incidentally, the once a year thing has earned them serious media attention and the billing as the "World's largest annual gathering of...". They even had a TV spot on the PowerBlock this year. That's a big deal, depending on your goals.
As for what to do between now and then? Go do it! Get out there! But cap it to something like 10 or 15 vehicles. And spread it out to different areas and venues. Don't get locked into thinking everything you do has to be huge or over the top. That will kill the fun for ya, and you'll end up missing kinda the grass roots of what started this in the first place.
For example, we'll be getting back to our 10 or so Raptor events out here in Death Valley and Anza and Barstow etc soon. And as much fun as those are, trust me the talk around the campfire will be about how amazing Trey's event was this year, and how some of us made it and how some of us wish we could have... and how we might make time for his "BIG" or "Super Bowl" Raptor event coming in 2013... you know, when whos-that-guy will avenge his defeat from last year, or where so-and-so plans to debut their epic build, or...
Just sayin