I have thought about this too.
And one thing you could try is to arrange 
to "buy" it through ebay. They could list it and 
give you the link. It takes a while for it to 
show up in the search engine so you'd buy it 
before anyone else sees it. If they worry that 
someone else might somehow get to it before you 
they can choose not to have a buy price, then you 
just bid on it and they end the auction right 
after you bid. When you end an auction you can 
choose to sell to the bidder. This way you are 
both able to give feedback to each other.

Just a thought :)
Sandra