Numerous Complaints is a great place but they deal more with Hammonds than anything. Yeah, they do take an occasional analog in on consignment. As a matter of fact, a couple of years ago I purchased a Matrix12 from Numerous Complaints; which may not be a digital synth but it is midi thru and thru. I also have seen midi'd Prophet 5s there and if memory serves correctly, even a Juno.
I'm not flaming anyone here (there are other sites for that) but please, don't forget age is relative and in some circles a person with 17 years of experience is considered a baby.