integrate auction software with WWF?

First perhaps I should ask if the ww-hosting would allow or support such a thing, then ask:

Is there a good basic auction software that would allow integrating itself into the forum?
We have a trading post area, but folks a time would rather sell things via auction.
Then there are those who prefer auctions, but don't really want to do the eBay thing.
I was thinking it could be a way to support the forum and help pay for hosting, etc. if we had some sort of simple auction setup - only forum members could use it, and a small percentage of proceeds could go toward the forum.

Thoughts on this?

We'd want the ability to lock it so only members could use it, and it would use the same sign-in or name and password to keep it simple.