i'm almost at break point too. its getting to the point where i'm going to have to stop mining and wait for it to come back up.
For what it's worth, I think you need to work on power optimization - if I read your chart right, you are pulling 702 watts to run 1.3Mhs of scrypt?
I run rigs that pull 686 watts for 1.8Mhs when using Bronze PSU's, and I am currently now purchaing Gold rated PSU's as they pull closer to 640 watts at the wall for the same setup. I still can't justify the increased cost of Platinum PSU's.
Have you explored undervolt your rig or invest in a better PSU, or different GPU's with a better power per kh ratio. Heck, with that power cost, you may want to explore ASICs, when they actually become more reliable.
I don't currently have a power usage monitor so I'm over estimating the power from my 290 and 270. I've got a thermal take 1500w Psu but dunno what it's rating is. I guess I'm playing it safe by over charging myself for power.