Thanks to Zach Baird at Raftfix.com for the warning and info about the boat.
Go talk to Ron at Riverboat Works in Salida. He'll have Hysides and RMR rafts, both of which sell small boats like what you're looking for.
By the way, all the businesses listed above sponsor MountainBuzz.
Nothing in the world is more yielding and gentle than water. Yet it has no equal for conquering the resistant and tough. The flexible can overcome the unbending; the soft can overcome the hard. - Lao Tse