I do not consider 50,000kH/sec (on scrypt) to be a large GPU mining operation.
I don't either, but it at least shows that a person speaks from experience, rather than theory. If you told me you operated a 50,000-100,000 kh/s farm, and you were able to design it as you indicated and make a ROI in less than 8 months, I'd listen much more intently.
You're correct that I have not offered evidence of such. And I will not be at this time. But we'll revisit this question at a future date when no cryptocurrencies are still feasible to mine with GPU's. No one is going to believe anything without photos (and even then, photos are routinely disputed on this forum), and that will not occur until GPU mining is dead. Same reason no one else has posted photos of large professionally-operated GPU farms. Take it for what it's worth, that's the best I can do for you, aside from the hints I've already dropped in the couple threads on this.
I think the overall point was that with the challenges that a small 50,000 kh/s farm brings, it's very unlikely to bring up a farm 40+ times that size instantly.
Ah, but it wasn't built instantly, it was built over a longer period of time for mining BTC. The transition to LTC and the "hey, everyone check out the hash rate of that user on that pool" stunt did take a couple days, but that's not the length of time it took to build the farm.
That type of power consumption would not be under the radar.
This I'll agree with you on. But there's no reason to believe it operates or needs to operate "under the radar". If what you mean is that everyone everywhere will be aware that there's 700kW entering a building somewhere in the world and a column of hot air exiting a HVAC cooling tower adjacent to it, that part is not likely. Large industrial customers routinely consume several MW to tens of MW, a single customer under 1MW is not going to attract any attention at all.