With that said I challenge anyone to show me a scenario where an SP31 is the best option.
From where can you buy AM Tube at that price?
I mixed up the power consumption, it should be 1.09 w/gh not 1w/gh when overclocked. It's fixed now and the tube is still the most profitable. It's ~$1700 more profitable than the sp31 in half the amount of time.
Each tube is ~0.96 btc each and can be overclocked to 920 gh/s at 1000W. A modded server PSU is ~$25 per miner.
Yeah, you've missed quite a lot here... for instance, spec'ing up a new machine with a second hand sever PSU? That is not a fair comparison but adding in the $170 or so for a new PSU for each tube would really screw up your figures, wouldn't it? No warranty, no guarantee on power factor etc, etc.
You really need to let the ventriloquist who is moving your mouth for speak directly. You're making up stuff, including your power consumption figures and while people who aren't proper engineers might be satisfied with them I know fine and well what you're doing. If you want a fair comparison, get a proper vaildated spec for the tube and it's actual power consumption, that mean the real power (resistive and reactive) drawn from the wall that appears on your bill.
The ST guys use proper performance figures and they also use an expensive server PSU that has active PF correction, their 3000 watts at the wall is what you'll pay for. Your figures are all over the place, just what I'd expect from an amateur, take best case yours and worst case theirs, and throw in some second hand equipment costs for good measure. You're an idiot.
I'm really busy with my job just now so don't have enough time just now to do this comparison for you, but I will get round to it. You're obviously not up to the task and can't be impartial.