It looks like a great idea, and the bobbin seems very large, like something I'm looking for myself. However, I'm concerned about the contraption on the pedal part.
One side (right) drives the wheel as you would expect. The other side, however, is a pulley that pushes the rod up. I would really want to sit down and test this mechanism before I purchased it. It must be absolutely smooth acting with no jerks or hesitations when spinning. You might get by on regular wool, but try to spin silk, angora, etc, and you'll get frustrated. I'm not saying this WOULD do that. I'd just want to test it first.
Cheers, and happy wheel hunting.
(BTW, I second the Babe recommendation)