My work brought me to an aerospace contractor in the area who was getting a shipment from a fuel cell manufacturer I'd never heard of.
A quick google and I learn that they are a cell manufacturer for F-15, F-16, F-18, C-130 among others. May not amount to anything of interest to auto racers, but it might be another possibility for those in need.
Just thought I'd share:
http://www.amfuel.com/index_start.htm