One of my favorite websites, www.woot.com, is having a sale today only (April 1) on the Black & Decker CP120B Backup Battery. You get two for $15 and shipping is $5 for each group of six.
They are 1.2Ah NiMH batteries. More info is at woot.com. I have no idea how suitable they would be for EV applications, but this seemed like something someone here might be interested in.
Jake
The Rezistor: 1970 Vespa smallframe conversion