think what he's doing is much different than offering it for
outright sale really. He's simply giving himself a chance to get the best
price he can while at the same time offering it in a way that remains fair
for the buyer.
I like the idea of items being offered for sale to the group but, I
don't like the idea of bidding (secretively) against my friends.
Something for people to at least consider is to offer items as, first
reasonable offer. The catch here is how I would define a reasonable offer;
either a price I personally set (whether I choose to reveal it or not), or
a price that no other bid exceeds by say 50%.
The idea here is to arrive at a "fair" price, with a process that isn't too
slanted in favor of the buyer or seller.