So far, it looks like we have 100-110 racers on the grid. We expect to get 60-70 runs per hour, or over 500 runs in if all goes smoothly. Last year, with a field of 94, we had about 20 racers hot-lapping during the last 2 hours of the event, and one racer made a total of 22 runs. So, I think you can expect to get several runs in pretty easily.
Edit: Current Grid list is now posted on the Mojave Mile forums. I'll see you all (that are coming) this weekend!