DH made me something very similar out of wood. It works the same way as this one. Before I got my mid-arm and frame, I quilted a lap-sized quilt on the the frame he made. It worked okay, but the PVC rollers were a little awkward to maneuver, and since the frame moves instead of the machine, it took the whole length of my 9' sewing room to quilt that small quilt. I personally wouldn't want to try to quilt anything larger on it.
But for as little as it cost to make ($15 or $20), it was worth it. :D