12U, 16kw, 10 replaceable hashing boards.
IMHO, if you came out with something like 4U/5Kw/3 or 4 board version in the 20-25TH range you'd make a killing. I think that would still keep the home miner in the game as basically anyone with 5 SP20's running today should/would be able to convert over to this. As with the SP30/31/35 the rack mount form factor would be great for those of us in a datacenter setting.
I would absolutely buy one of your third generation units at a 4U form factor, i can not imagine it costing you that much more to release both form factors simultaneously. Since if you did released it to industrial miners first they would have the advantage of the new ASIC technology before the home miners giving the industrial miners more of an advantage. Releasing both form factors simultaneously however would create a more level playing field. You would also gain even more respect then you already have amongst the Bitcoin community. Furthermore in the long run this might even be the most profitable strategy for spoondoolies, since what is good for Bitcoin is also good for spondoolies. that is one of the beautiful things about Bitcoin, it is supposed to align incentives towards good.
