Based on all that i've read here, if you DO want to use nitrogen, a bottle connected to a foot pump with tire pressure gauge would be the way to go. This way you're just using your leg to inflate the regulated input from the bottle vs a motor.

If you want to be realy silly and use an inert gas, i'd suggest xenon, as it is a very large atomic mass. Helium would likely simply escape through the pores in the tube.

- Andy