Brilliant ... looks like the love child of a biscuit joiner and plunge track saw, now he just needs to introduce it to a router and hope for a gifted child that can do both bases and sides.
Seat of the pants thinking, but seeing it in action, he can only go so far end to end and I think it should have a smaller diameter stone to allow for closer spaced edge rollers (bearings). Also, a pattern of 4 or 6 rollers on the base to more precisely follow the tip and tail rise (or dip in this case with ski base up).