I have tried the 10 gallon air tank and it does work,just doesn't fill the kite all the way.Then you have to top it off with a hand pump.just ends up being more gear to carry around.Unless you have a crappy pump and are pumping large kites all the time,a hand pump is fine,just part of the program.
I have looked at a couple of systems that uses rechargeable co2 or rechargeable air tanks, but unless I can find a system with local companies where I can just exchange empty for full bottles. I would prefer to use a standard air compressor do that I don't have to continually pay for recharges.
At the moment I am thinking of a 10 gallon air tank filled by a 12v air compressor to about 100psi.
From what I have read in other posts, that seems to be a good combination to get at least one full kite inflated. I'll look into it more and post my thoughts and progress. I am however thinking of incorporating a Venturi device made by a company called volo. Their website is pumpkiteup.com. By using a Venturi to draw air in externally from the bottle, they reckon that they can get 40% more efficiency for a tank full of air. I just need to find out if it will work with pressures as low as 100psi. Maybe it will only work with 200bar pressures.