Some things I want to do to trim my power is flash and downclock the memory of my 4 6970s and also downclock/volt/whatever the CPUs. Not sure how much that will really save me though.
Modus, when you say downclock the CPUs, are you talking about the actual CPUs on the motherboards or just the GPUs on the card? If it is in fact the CPU, even with free electricity, I wouldn't have thought the risk of burning a CPU out would outweigh the extra ~10MBs you might be getting from them.
Nice setup by the way! Is this outside, in a three seasons room perhaps? If so, is humidity of any concern for you with the exposed cards?
Thanks for sharing!