Great DIY project! I'm going to have to make a few of these myself.
These instructions remind me of this great book on 'homebrew' filmmaking rigs:
http://www.dvcamerarigs.com/Most of the parts can be bought from a local hardware store, plus a few parts from specialty places like wheels from skate shops. The only rig I've made so far is the dolly, and it works very well. (I got my wheels from
www.skates.com) The other rigs in this book look pretty interesting; there are instructions for building a crane, a balloon rig, and other handy rigs.
Greenlaw