I've had a couple and they were still going when I decided to upgrade.
There are sites that deal with just refurbs...might be better than ebay, or at least worth checking out.
The place I've bought from and still refer friends to is
http://www.microexchange.com
Their inventory changes constantly, but they seem to do a great job getting orders out immediately, and I've not had anyone I've referred to them have problems as of yet.