H720 PSU?

With the recent discussions of the PDP-11/20, I've been thinking of what all I'll need to gather to restore mine. It's been a long time since I pulled things from the pile, but I'm pretty sure that before it was pitched, the fans and PSUs were harvested. I've found pictures on the 'net of the fans - looking at the wiring, they appear to me to be pretty standard 110VAC boxer fans. ISTR hearing that the fans in the 11/40 or 11/45 are bizarre, but I'm expecting that the fans in the 11/20 are ordinary. This leaves the PSUs. If I were going to go with MOS memory, I wouldn't worry about what to use - the Unibus itself only needs to provide +5V, and +/-15V. Because the 11/20 routinely held core, it's expecting +8V (unreg) plus -22V on top of the usual voltages. Since the "easiest" solution is to get the original equipment reattached, I'm curious how much an H720 might fetch these days. If it's too much, I can always come up with some other way to provide power to run core (or skip the core and use MOS). My question for those that have tried recently, is it feasible to go searching for 1-3 H720 PSUs, or are they old enough that the chances of running across them are slim enough to make building a functional replacement a preferable go (preferable from the standpoint of ever being able to finish). Thanks, -ethan