Web search for PC/104 and you will find lots of information. You can still buy this stuff new to all kinds of specifications. This spec was done primarily for industrial uses so the new prices tended to be higher than you might expect.
If I remember correctly they used the ISA bus for power only.
My knowledge is rusty though since the last I seriously looked at them was probably about a decade ago. We built kiosks at a University and I had the idea to put 4 of these in an enclosure. It would have been smaller form factor and detracted thieves but we could never get the price down low enough.
The only wow factor you really get from having one in your amiga is in fact to say "look its in an amiga."
If you do go for it and use a board with any significant CPU power make sure your Amiga power supply is up to the task.
