Look at the NOBSBatteries 1950 NiMh packs... much smaller and lighter than sub Cs, and since you're into numbers, each cell only has 5 ohms of resistance. They are capable of 40 amps. I use them on my ignition and there is virtually no voltage drop with a 1 amp load.

Before you start talking about how "fragile" NiMh are and quoting Red's 10 year old articles, these are a new generation of NiMh that are much more robust and durable and not so temperature sensitive... like NiCds. Just took the tech a while to catch up.