A big thanks to the folks at ddrfreak.com for all their help!
Here's the pics from our pad! ^__^

This is what the inside of the arrow panels look like. There's a duplicate of this panel sitting above it, but with plexiglass, not wood. The gray lines are weatherstripping, which compress so the two metal sheets make contact.

I took this picture, so it's Alex, Mike, and Byron grinning next to the unfinished frame.

The wiring inside the pad. There's a ground and contact wire for each arrow, and a ground and contact for each push button on the control panel (bottom left).

A close-up of the bottom of the control panel.

And, the top of the control panel (not attached to the rest of the pad yet).

Our homebuilt metal pad next to the storebought vinyl pad, mounted on a sheet of wood.

Mike and Byron playing on the pads (sorry I cut off their heads!).

Mike playing on the pad.

Isn't it gorgeous? ^___^ Note the cords... the yellow one connects the pad to the controller, and the controller connects the whole setup to the PlayStation2. ^_^
Hope you like it! ^____^