That was actually my original plan, to build a wooden rig (mine was going to be single tier, since I'm short and didn't want to deal with the taller structure, haha). But the little voice in my head kept saying "Wood, 165,000 btu burner. Extremely flammable material built to house an extremely powerful heat source. Fire, fuel." and that stopped me from getting started on it. The potential for shennanigan was always in the back of my mind.
Granted, a few folks on here have built wooden stands (search for "Scuba Steve's Stand" and you'll see the best example of it) but it wasn't for me.
You at least have welding experience, which is more than I had when I built mine. I just showed up one day, spent a half hour running some practice beads on a piece of scrap, and then got to work. 30% welding, 70% grinding. They're still not pretty, but they do the job.
If you don't wanna weld, check out
http://www.brewersequipment.com/New Brew Stands.html. Those prices are shipped to your door. If I hadn't lucked into meeting someone on here that took me under their wing, this would absolutely have been the direction I'd have gone, plus they're HBT supporters, and I think plenty of folks have said really positive things about their stands. (Bear in mind these are bare bones, you still have to add the pumps et al). But when I built mine, the cost of the stainless square tubing alone was $200, plus another $75-$100 in grinding and polishing wheels, plus other supplies. Then the cost of labour, it was at least 40 hours of work in the shop over a six week period. (But to me it was worth it to have the satisfaction of seeing it and knowing "Wow, I built that!") So can't argue with the prices of these.