I heard many people using the 12vDC T-Rex Fuel Tank power supply with time factor. And after many months of use no problem occurred.
I tested the durrent draw of the factor and it not exeed 410/420ma at 9 volts, even in intensive use or long delays. I didn't tested the looper function.
I think that the easy way to solve the problem is to contact some amp/guitar system builder and ask for a custom power supply with 3 or 4 regulated and isolated 1A outlets. Probably is the cheapest and better solution.
I also think that is absurd that a stomp uses such a big power supply. We are in 2009 not in 1969…