What about a foot pump like this
http://www.amazon.com/Intex-Giant-Be...ress+foot+pump
And the air bag that I posted earlier would be pretty light weight, operate without battery or engine power, and store pretty compact.
The pump weight is 2 lbs and packs flat, the bag kit weighs 10 lbs, but that includes the big hose and funnel, gloves and a different hose and tarps...you could pare that down to just the bag for a bike so maybe 3-4 lbs for that...under $150, worth a try. Return it if it fails.