In the next month or two I will be building out a site for a friend. He is looking for it to be a silent auction site where he can post his antique products along with a end-date/time. He would also like a minimum accepted field that the customers would know about. Customers will be able to put in their highest bid and then upon the deadline all bidders would get notified if they won or not via email. If none of the bids exceed the min-accepted amount then all bidders would be told they lost. Perhaps this could be an option where all bidders could instead be told that the reserve was not met and the deadline is auto-extended another 24 hours.
If this was built out as a wpmu plugin that would make things much easier than me trying to hack it. And if it was built compatible with multisite then I could build out a network of sites all using it.