I have no business sense, so while I applaud your effort to sell the bike for your friends' benefit I won't pretend my advice will further that goal. That said....

Seems to me the best thing to do would be to document and publish the bike in the most visible way possible. Make it famous. A photo essay in a mountain biking magazine would be best, I think, or in a general cycling or outdoor magazine. The accompanying article should include the prototype Yeti frame above, and period photos of the people involved in the process, and, of course, extensive documentary photos of the bike in its present condition. And there should be photos of the bike's evolutionary descendants. The goal of this article is to (1) get as many people to see the bike as possible, and (2) to provide ready access to the bike's history. Somewhere in that article there might be a reference to an upcoming sale; but keep the sale itself separate.