I simply bought a bunch of 500VA APC computer battery backup power supplies when my local Staples office supply store was clearing them out. I paid $15.95 each (dirt cheap!) Of course they didn't come with all the "monkeynuts" power adapters that your unit has, but I don't need those - I have all the original AC chargers that came with all the gadgets I'd every want to charge. If I need 12v, I have a spare computer power supply that I can plug into the APC battery backup unit. I haven't looked to see that the battery voltage is inside the APC unit, but if it's 12v then I could just get it directly from there, avoiding the inefficiencies of converting 12v to 120AC and then back to 12v again. If I really need more power, I'll just remove all the backup battery supplies from my computers and my digital piano. I've got a good 1/2 dozen APC units available. If the APC internal batteries are 12v, it would be easy to jury-rig a car battery to power the thing if needed (we have lots of cars!) Or use the car battery with the inverter we have.

How much does this PowerGorilla thing cost? And what is it's power capacity? Judging by the size of it in the picture, it must have a pretty small internal battery. Your specs mention voltage and amperage capabilities, but specs are missing telling us how LONG it will be able to hold up it's output. "5v at 1000ma" is all well and good, but will that output level last for five minutes, or five hours?