[ZoFreX]

Converting voltages is trivial with AC, how do you handle devices that require something other than 12v (lots of phones want 5, lots of laptops want 18) with a DC system?

[webignition]

I'll be fitting some 12v-based USB wall sockets, much like the type you can fit in a car. These can then provide power for phones.

Regarding computers, I've so far only considered my desktop. You can get ready made DC to DC ATX power supplies quite easily [1].

[1] http://www.mini-box.com/DC-DC