Check out a123.com. Maybe they could help you out with the new batt chemistry.
a123systems batteries are probably out of your price range. The 3.3V 1.1AHr cell costs $10@100pc with tabs welded on. It can deliver 30A continuous and 70A peak as I recall.
The 2.2AHr cell costs twice as much and can put out 60A continuous and 100A peak.
They have the side benefits of being intrinsically safe and only lose 10% of their capacity after 1500 100% discharge cycles.
a123racing.com has actual electric vehicle testimonials and youtube has safety test, electric dragster and electric motorcycle videos using the A123 cells.
Dan