Sounds like a battery UPS (uninterrupted power supply)would work.
I would check computer stores and suppliers. I know Fry's electronics sells them, unsure if newegg does.
The other thing is they may not supply the voltage or amperage required. I have never actually researched this from the save the heated reptile aspect. Just for CPU's.
I would check and see what they have available, keeping in mind you may need to build a seperate back up heat system one that works on low volts.
Good Luck
-----
Jeremy
"I am become death, the destroyer of worlds" July 16, 1945 Robert Oppenheimer
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