I'm surprised that Amazon hasn't ventured far into the used market.
Initially they were a new/used book store. And the books had a stock ad, and were rated good, fair, downright grubby, etc.
But, it shouldn't take too big of a leap in concept to make a general category ad... Campagnolo Nuovo Record Derailleur... then link to specific ads by each seller. Amazon fulfillment would take a hit, but not everything has to go through Amazon fulfillment.
There have been items that I have chosen not to order on Amazon because the general ad didn't match the individual listing with no additional information provided. For example, a used multi-volume encyclopedia set for $5.
In theory, you should be able to sell anything that is truly NOS/Boxed on Amazon. Perhaps even "good used".