I'm looking for some sort of opaque/translucent panel.  I have two
73 X 73 open-backed bookshelves (Ikea Expedit) that I'm putting back to
back.  I want some sort of panel in between that will hide the contents
of the backside, but still allow light through.  Glass is too
expensive, but I'm hoping there is some sort of frosted/opaque plastic
material I can use that would fit the bill.  Plexi is really expensive
too, but I know there's other stuff out there.  Any suggestions on what
and where I might source it?

Danka.

Hey, Micheal.

I agree with the comment in the other forum about polygal.  I don't think it will be inexpensive though.  I may be wrong, though.

Look at corrugated plastic or fiberglass panels.  You can find those at the local hardware store.  If you can get some with a smaller radius to the corrugation, I think it would look better.

An example would be what they have on the banisters over at BJ's restaurant on Pearl St.

Good luck.