I've built my own stands... I do enjoy building things - I too purchased almost all of my tanks from craigslist...
If you keep your eye open, there are some very good deals out there..
A 29 gallon won't be too heavy, but I found some good plans on-line by just "googling" aquarium stand plans... just remember, you need to build something that will hold about 300 pounds.
Good luck, I'd enjoy seeing pictures when you get your project set up.