Just made one up a few weeks ago from spare bits for a total cost of £0.00 - and it's excellent!
I loaded the 5v rail with an old automotive bulb I had around and it puts out about 12.5v on the 12v rail consistently.
On/off switch was from an old Tamiya MSC, I think. Binding posts were scrounged up from somewhere, and the PSU was discarded by a friend who was upgrading his machine.
