Wish I could take full credit for the pump... Del Canty's tube from the 80's came with a silnylon bag with a nozzle built in to inflate his tubes. The "problem" is that it weighs nearly half a pound and you have to overcome the flapper in the valve to inflate the boat. Also, the silnylon and the seams aren't fully airtight so you lose a good percentage of your captured air.
With my system, I built a flapper-pusher into the nozzle so I have zero resistance inflation. Add to this the HDPE trashcan liner is airtight and stooopid light so there's hardly any weight penalty. Plus, in a pinch you can use it as a poncho or a tarp. Hell, take a spare!
_SHig