[Carding]

Arya's auctioneer script (which I think there are updated versions of on the runUO forums) operates in much the same way as ebay/the WoW auction house in that you can choose reserve, buy it now etc. and set a description. So if you were going to implement something I'd look at that.

However, having said that, I kinda like giving players reasons to use player vendors and trade directly. So I'm not sure if I am personally in favour of it, perhaps you could allow the auctioneer to only be used for high end (high reserve/price) items, kinda like an ingame version of Christie's...