Power Supply For a Supergun

I am currently building a supergun around a MV-1F board, and was wondering what kind of power supply I should use. I know that I should use an AT rather than an ATX power supply, but I haven't found any with a power switch on the unit. Help!

I have a similar setup.
I use a standard Comp USA 250 Watt AT Power Supply.
The power switch is not on the supply itself, but rather, at the end of a thick cord.

An atx Power Supply works fine, if you want a switch, just put it on the light-green wire (there is only one) and a ground. when that wire is grounded the PSU will come on. exact same as a AT.