I've finally got a 1.0 release of the Alumni site up and running on a dev environment. We decided to migrate the site from D5 to D6 now since we were basically at the ground floor. This was a tricky decision because there are definitely lots of modules that are still in development that are pretty critical for any drupal site. However, Views and CCK are getting very close and a few others will follow close behind them once they are ready. Ubercart was another module we had our eyes on which is still under heavy development, but we aren't planning to use this for several months at least so that wasn't a huge draw back.
You can check out the site here
http://aandev.plumbob.org
Our development has been somewhat slow because the 4 people who have been working on thi have day jobs, so this site gets a small amount of time each week unfortunately.
Our hope is that there are some people in the Drupal community that know about Arcosanti and Arcology and want to lend a hand in building a tool for the community to get active!