try these guys,

http://www.batteryspace.com/

they have pretty good prices and a nice website. They even have those
sub C used in the cordless drills.

I've done a lot of rebuilding and even rejuvenating.

I rejuvenate batteries that are shorted by charging a capapcitor like
50,000 uf to 50 volts and then apply it dead short to nicads that show
a short. It usually blows the internal batteries short and gives it
new life. Not always but sometimes it fixes it for a long time.

PLEASE WEAR SAFETY GLASSES when you do it. Molten metal can fly.

good luck

Don