For just the 55nm chips, I'm spitballing numbers that look something like, $500 a wafer, 200 chips a wafer, 2gh a chip, 10c a chip for balling and packaging. So about a buck thirty a gigahash in chips, say a buck 50 with NRE amortized over a crap load. Probably $2 a Gh our cost by the time they are on boards...
If the numbers come close to that ballpark, it's making sense.
Those numbers seem way off. For example, Bitfury chips get around 2GH/s and they probably get ~4k dies out of a single wafer. Your cost for a fully processed wafer is also low, though not enough to even out with being possibly 20x on the number of chips.
Cost should be a lot lower than $2/GH/s at the board level to have chance of being competitive though. Cointerra is selling May delivery units in a chassis with cooling, controller and power supplies for $3/GH/s, and that's including markup to cover overhead. Cost for a 55nm product with chips shipping even in Q2 will have to be way below $1GH/s at the board level to be sensible.