Mindwalk set up the Yip! Shared topic (from the main menu) which I think was intended to over this service - either by advertising your search for particular material or itemsyou have to trade.
The thing that may inhibit use of this is the ftp functions are tricky - but once you figure it out, it's easy.
I'll expand on that or clarify that in the Yip! Share topic.
To my knowledge, the greatest hoarder of Daniel Johnston bootleg treasures is Peter Holy, who is a member. Hmmm.. I'm not seeing him on the Yip Jump Board list.... it seems like I saw a post from him...
At any rate, the LINK on the MEMBER LIST of rejected unknown.com takes you to his list.
http://www.fsmat.at/~pholy/