awsome hack. ill like to make one myself, but i need a welder.
You can get good used welders for very reasonable prices. I'd recommend checking out a book or two on welding processes from the library, and then shop at some local welding shops for used units. Let them know the kind of work you'll be doing, and they'll help you out. You'll probably be looking for a MIG welder that works with 120V power, and can do about 80-100 amps for bike tubing.
And when you finally finish your project, make sure you post a picture.