Sit on top inflatable sled for packrafting?

http://snowsleds.net/email-a-friend.aspx?product=292

This one is only 6’ long and 2’ 7"inches wide with lots of rocker. You sit on an elevated mesh floor that would drain water, plus it would be easy to climb off of. Looks like you could paddle right over rocks jutting out of the water without it even scraping your floor. It probably weighs a lot more than an alpacka, but should be durable. Looks like it could be a great boat for exploring small creeks and bony rivers. Maybe Alpacka should experiment with this design. This is selling for $100.

Or why not go for a Ruta Locura Lwd-Ul at $175 - the reviews all have them on flat lakes where they look hopeless whereas going down a river with a bit of speed they might be quite good.