I think it would be funny if pid.bungie.org still had stuff to update with, even after Halo PC's release (actually, it would be even better if it was updated at the same time as the Mac release). So.... who wants to catalog the interesting things in the PID Shapes?
I'd recommend you use Loren Petrich's shapes dumper; it's much less buggy than the program I used to dump the shapes out originally (mine made the walls come out wrong). It's at http://homepage.mac.com/lpetrich/PIDCode.sit. If you don't have a copy of Pathways, then you shouldn't try to do this ( ;) ), but you can do it anyway with the stuff in http://astrange.ithinksw.net/pathways/ .
David Coufal's website with the A1 Demo has been lost to the mists of time. It might be on www.archive.org, or I might have the shapes file, or Hamish almost certainly does. I remember the only interesting thing being the items collection, which is in http://astrange.ithinksw.net/pathways/A1DemoShapes/ .
As for me, I'm too busy to do it, but I'm not too busy to tell someone else to do it :)