Still it looks like you just assumed everything is operating at 0.7 J/GH.
Meanwhile full sized miner is falling quite a bit short (10-20%) on hashrate, but the powerconsumption is.... 250W AT THE WALL.
That would be between 320 and 360 GH/s at 250W = between .7 and .8 J/GH on a 55 nm product. I seriously hope the 28nm products can beat Bitfury's 55nm by a significant margin.