My vision could be called NxtPrivateMarket, as opposed to the Nxt asset exchange, where product names are public, and which has a listing fee.

The private market would be implemented by program, which responds to messages coming to its Nxt address. The buyer sends a message and coins to that address to complete the transaction. The buyer side doesn't necessarily need a specialized program, any Nxt client will do if it can send encrypted messages. (I don't know if the Nxt clients already support that.) Perhaps a more user-friendly buyer-side program would be needed to get users.

If nobody is willing to implement this for a bounty, I can try to do a proof of concept of this myself.