I'm in possession of a Psygnosis / SN Systems PSY-Q CD Emulator System board, which apparently was used in PS1 (and maybe Saturn?) game development as part of their PSY-Q dev kit setup. No idea if it works or what its value might be to a collector; hesitant to just bung it on eBay as it seems to be very obscure and specialist.

Documentation's out there for the PSY-Q system itself, but the CD emulator board only crops up in this one archived listing, where it apparently sold for $138... no idea when though:
https://picclick.com/Vintage-Psygnos...281369588.html

Opinions, anyone? Happy to entertain offers too, if you're so inclined.

Click image for larger version. 

Name:	cd-emu-2.jpg 
Views:	52 
Size:	128.4 KB 
ID:	10853Click image for larger version. 

Name:	cd-emu-1.jpg 
Views:	10 
Size:	129.6 KB 
ID:	10852

(Note the rather ancient sticker on one of the ROM chips declaring it "working" as of 1997 )