Just in case any previous posters come back:
Jdubbery - I have a tripod stool similar to the one that you mentioned from REI and it is easy to DIY. I tested this with 1/2" emt and a 1 3/4" brass ring and you can pretty much set the height at different levels and if you can sew a hammock or tarp you could make that chair. The one I have weighs at least as much as the stool I built and showed in this post, but I promise mine is more comfortable and safer if it failed. I realize it's more of a short hike, car camping accessory, but it was just for fun.
BigBamaGuy - As I mentioned in my post, my brother is 280lbs and it held up very well to his use. I would probably worry more about the straps than the pvc itself. At least in the beginning.
grich9860 - I love the idea of the hammock chair and will probably make one for myself. The drawbacks to that chair are that personally on trips I have taken in the Southeast I don't normally come across 8ft limbs that aren't somewhat rotten by laying on the ground in the moisture, so raw materials can be an issue unless you want to cut down trees each time you set up a new camp. If you're on a multi-day hike you might not be able to guarantee that you could build one. Finally, the footprint of those chairs is a little big.
All in all, I'm not looking to convert anyone to using my design and I appreciate the conversation surrounding the stool. I just wanted to put something out there and see how it was received. You guys inspire me and it is nice to be around like-minded people, even if only virtually!