I really like the idea of player-run auctions, but I think that they should be just that: player-run, as opposed to prog-run. For example:
Buddy says 'I have this wonderful belt of rabid rabbit hide for sale here.'
Buddy wears a belt of rabid rabbit hide about his waist.
Billy says 'The bids start at fifty platinum. Do I hear fifty platinum?'
Billy raises his hand and says 'Fifty platinum.'
Buddy says 'Do I hear fifty-five?'
Joanne raises her hand and says 'Fifty-five.'
Buddy says 'Do I hear sixty?'
...
Buddy says 'Going once!'
...
Buddy says 'Going twice!'
...
Buddy says 'And SOLD to Joanne!'
Joanne gives Buddy some money.
Buddy gives Joanne a belt of rabid rabbit hide.
And so forth. Perhaps, though, someone could build a small area dedicated to this and link it up to other areas. As there is an auction house in Waterdeep, there aren't any in other cities, so far as I know.
I really like the idea, though! It could spur on some fun RP

.