We made one in high school with a couple electric leaf blowers. It was really basic, but worked pretty well.
We took some 2mm thick vinyl silo cover material (farm kids), a 4 foot circle of 1/2 plywood, some lath, 2 blowers, a coffee can bottom and a 4 legged chair... threw it together, and we were flying all over the gym. I weighed in at 230lb at the time and it halled my ass around like I wasn't there. It actually didn't work worth a crap without a load on it due to where we cut the holes for the skirt.
To create the skirt, we cut a circle of the vinyl to completely cover the bottom of the wood, but not tight. We tacked the edges of the circle to the top of the wood with lath and silicon caulk to make a seal. We left enough droop in the cover so that if you pulled on the center of the circle of vinyl, it would come away from the wood about 8 inches. We then cut the bottom off the coffee can (it was all we had laying around), drilled a hole in it and mounted it in the center of the bottom through the vinyl with a bolt through to the top. When you lift the whole thing off the ground, we created a half donut with the sagging vinyl. On the inside perimeter of the droop (toward the center), we cut a circle of 1 inch holes. We also cut a hole in the top of the board before we started so we could jam the nozzle of the leaf blower through the wood.
So basically... screw it, to hard to explain.
Sorry for my inability to draw... You'd think that would get better with age?
You could also go the route of one engine and make a little bit of duct work. A little more complicated, but would only require one engine. I saw one like this get made on junkyard wars a few years ago and it worked really well.
Basically, you only need about 1/3 air flow to support the skirt, the rest is used to propel it forward. This would also make it more stable and less likely to spin on you.
Again, sorry for my drawing inability, just trying to help you out is all.
