dc ups pc power supply

We need to have better PC power supplies.

There is no need for a UPS that converts AC to DC just to go to the powersupply via being turned into AC just to be turned back into DC

What we need are protected 12 and 5 volt rails, that can take a bit of wierdness when a battery is plugged in or removed.

I think it could look like this:

Wall-AC---Powersupply-mobo and stuff
|
12 and volt regulators?
|
Wall-AC---charger&Batteries, not always being charged, but always available.

I don't know how complicated this would be. It makes my head hurt just to think of how the voltage gets regulated.

I'm also thinking that there might be inefficiencies by having two possible sources of power, and either one of them can go out at any time...

I think there should be a plug in the power supply for an external powersupply....

I'm shure that datacenters have these.