Check this out. Seems like a promising alternative to centralized markets.
https://medium.com/@BlockchainFoundry/blockmarket-desktop-release-date-d3a63acda1ed
edit: Oh just a quick sidenote, it's completely unregulated. Even the developers can't take listings down from it. Seems perfect for the DNM.
Been following this since the early days. Very good tech and a dedicated team. They'll be guarding against illegal selling though.