After dreaming about making one for a long time, I finally went ahead and did it. It was a lot of fun to make, and it worked pretty much as advertised. The biggest problem I encountered is that I was over driving the fan motor and I probably could have chosen a more powerful one that could have handled more tubing (more weight). I will solve this problem for revision two.
Anyhow, without further ado, here is how to make your own.
Step 1: Go get stuff
A box fan
A 1' foot metal tube with a diameter slightly bigger than your motor shaft
A rod clamp slightly bigger than your metal tube
Step 2: Take apart the fan
Forcibly pull the fan blade mount from the motor shaft.
Step 3: Measure
Also get a rod clamp with a set screw that can fit around the tube.
Step 5: Strip the umbrella
This may require breaking, bending and/or sawing off a clamp at the top of the umbrella that is holding the cloth in place.