I have used a couple of speaker stands designed for heavy speakers, picked them up cheap as a DJ store. I also have nailed a green cloth to a wall which worked very well Just make sure it is tight.
Cool! But too pricey for my pocketbook. Too, I'd bet my head against a footage that they used the Ultimatte with it for the sample video. To get a green/blue screen suitable for what most of us here are doing, it has to be a nearly perfect and uniform from corner to corner as possible--no wrinkles or shadows. You don't have to worry about that issue using Ultimatte.
In the for what it's worth department, that sounds like the same material Kubrick used back in the late 60s for shooting the shots with the ape-men in the opening sequence of 2001. Same exact material and lighting (although it wasn't blue/green LED). Actually, he projected 8x10 location plates onto the screen. The light from the projector was weak enough that it didn't register on the actors, but the little lenses magnified it and reflected the "projected image" straight into the camera lens.