Mark,
Your firmware doesn't support overclocking, correct? Any chance you'd consider adding it into your next version? I want to try your firmware, but I run my A2s at 1300MHz since the W/MH scale very well and my power is cheap enough.
What kind of performance/power usage are you seeing at 1300MHz? I'm seeing about 9.58W per MH on one of my units, and about 9.14W per MH on another unit. I don't have stock fans in my A2s, so my numbers may be a little different than others (the stock A2 fans are nearly 25 watts a piece, so I put in some more efficient fans).