I've added 2 new homemade links. Celtickane has a really good idea for a pullup bar that attaches w/o hardware to a I beam. Something real similar might work if you had a real solid door.
Dave Draper's link has a ton of ideas, including drawings and measurements for a lot of equipment made out of wood.
Toffe's Gym shows an INCREDIBLE homemade gym.
I've added a few more!! People have been busy making and documenting making things, thats COOL! I wish I had time to comment on them, but...
A side note to anyone trying to get a hold of me. I'm working on a very short term, 2 to 3 more weeks, online project. I have to devote most of my computer time to it, so correspondence might be slow for a while. I'm sorry about this, but I need to make $$ when I can.