Fluid Spice, Jackson Fun, Necky Mission (will be harder to come by), Bliss-Stick S.C.U.D., Pyranha Stretch/Ammo/Z.One. Just look for a playboat with a slightly lower stern for surfing, and if he doesn't plan on playboating, a boat with higher volume. The Diesel is a good boat, but the plastic isn't as good as others. A Prijon Hercules/Embudo, Fluid Solo, Dragorossi Critical Mass, Bliss-Stick Mystic, Jackson Hero are all good river runners/creekers. I didn't put specific sizes because it all depends on preference and I am tired:( . Just make sure that he has at least around 5-6" of bulkhead adjustability and is not on the furthest up thigh brace setting. With river runners and creekers, he will probably be fine on leg room, but before you buy, try to demo or at least sit in the boat.