I will dont trust this, but use a more simplistic way.

I just bought Dell 1100W server power supply and it will rock (as any Dell/HP 750-1200 W PSU).

You just need to have some electro skills...

They are:
1) cheap (30-60 USD) (1/3 of normal supply)
2) made for 24/7
3) high power efficient (around 92% or more =  80 Plus Platinum and better)

Limitation is, that only making 12 V, so you still need "normal" PC PSU to power MB or some other way how to power it...