I'll sort out of some pics tomorrow if I don't forget
It's not expensive at all, well, let's say you can build one for under 150 (EMT plate reverbs were about 10 000!) euros I think. And it's not tricky at all really. You gotta be a little bit inventive. We used an old pc speaker for the input. You can use piezo transducer for the output most of the times.
For the plate, we built a wooden frame, and we drilled holes in the corners of the plate to attach/hang it in the frame. The corners are a bit problematic though, because the way we attached it causes the vibrations of the sound from the speakers on the plate to stop a little bit too soon maybe. So the decay could be longer, going to find a fix for that.
http://nicksworldofsynthesizers.com/plate.php
I think we used this as a guide back then
thats awesome