Thanks everyone for your comments and suggestions. I will monitor the usual suspects for a good used 80mm PQ or PQS to start with.
I know the usual ebay, b&h, adorama, KEH, Kurland - any other suggestions would be much appreciated.
Or, if this doesn't overstep the terms of this board, if anyone is selling, please contact me directly. (if this request is out of line, please contact me via email, and I'll edit this post immediately).
Thanks,
Matt