How do you figure the SP35s are cheaper? The price on 10 Prismas is 14.9BTC or 5960. To that you need to add 5*($45+$60+$3.50*8 + $10) for a DPS-2000BB/breakout/cables/shipping = $665
That's $6625 for 10 Prismas, which unless the SP35's have had a large price drop recently is still cheaper than two of those.
To be fair to RoadStress, I used $180 PSUs in my calculations and the price of bitcoin is fixed at 500 USD/BTC. Also, 2000W wouldn't be enough to run 2 Prismas. I don't know whether those server PSUs have the necessary PCIe cables so I was hesitant to use them in the calculations.
Can you provide some links to those products (DPS-2000BB/breakout/cables) so people will know what to look for?