I know about the Deltas; but this one is faster; you got it right, it's homemade.
All you'll need are propellers, which're commonly used on RC planes and a brushed DC motor.
About the blades:since you're probably not a RC enthusiast, you need to know that the 'pitch' is basically a measure of how much air the blade will more for a specific size and RPM.
i.e. if a blade has pitch 4, and other has pitch 6, and both of them run at the same RPM and have the same size, the blade with pitch 6 will draw more air and also load the motor more.
For the motor - I use a toy helicopter motor.
The result -- No fan in the market comes even close to the kind of airflow this one gives; at start, I should warn you, the thrust will be so much that you wont be prepared for it and the fan may just slip off your hands.
On top of that, it's cheap.
Ensure to glue the bade to the rotor after the final setup, cause in my case, it just flew off!