72v dc to 12v dc? I know the computer power supplies are stack able and can be used for dc projects such as battery chargers and such. The 12 volt sla batteries used in the ups still have a usable life for ev projects even after they are no longer good for use as a back up power supply.
Some people connect the ups to a larger deep cycle battery for longer service when the power goes out. Of course I doubt any of this can help you with the project at hand.
If you are able to sell the servers you got a few people interested here, but thats another story.
