Idea: A new decentralized marketplace that required a piece of hardware to access (microSD or flash drive). This would need to be purchased on the dark net. Buyers would be required to buy into the marketplace which would keep the community's population to a minimum. Vendors would buy into the marketplace which would limit fraud. Vendors would buy into the market at a rate triple that of buyers OR equal to the price of their highest listing until 100 5/5 verified deals were conducted. Whichever is greater.
How it would work
For a vendor to have a listing the vendor's flash drive key would have to be connected to the dark net. This would allow the vendor to have business hours just like a real dealer.
When a buyer wants to browse or make a purchase the buyer would plug their drive in and have access to a search engine. You have to know what you're looking for, sort of like a P2P network search (bearshare comes to mind). This network would need to be run through TOR to conceal the location of the computers that have their flash drives connected.
Plans for payment:
At the terms of the vendor.
Trusted Vendors with 100+ 5/5 verified deals that don't require FE as part of their terms would be given the authority to suspend or terminate buyer accounts involved in transactions due to lack of payment. This market is about trust. Vendors would be required to rate buyers and be given the option to decline selling to a buyer. Sellers could have listings with prices bases on the rating of the buyer. New buyer pays $$$$, trusted buyer pays $$$ or might not be required to FE.
Vendors with crappy ratings wouldn't move product so there is no need to allow buyers to suspend the accounts of sellers.
Note: I'm not a programmer. This idea could be totally flawed and idiotic. I am not capable of making any of this work. It is just an idea. Feel free to tell me why it wouldn't work. Why i'm stupid for thinking it would work. If you like the idea the best way to get it into the hands of the capable would be to upvote. This is a throwaway account.
My personal belief: the markets are already a super huge jump for your average clearnet user to understand and use. Tor, I2P, and PGP are very complicated to the average internet user. I know this because it can take days to teach some people how to properly do anything.
The above factor is a severe limit the concept of "eBay of drugs". The learning curve of the above severely limits the number of users capable of accessing an market. Honestly, silk road was nowhere near as big as it could be.
Now on to your idea. In the whole of things, the amount of users the markets see is already limited. There is no need for the creation of a "web of trust" market, yet. And again I say: yet. We have no idea what will come in the months and years ahead.
Also, could possestion of one of the hardware be used as evidence against you in court? Also, this design does nothing to stop LEO from coming in and evaluating what's going on.
TL;DR? This is an OK idea, but is not needed at this time...