I checked all the mirrors earlier this evening. I removed the ones (at least for the moment) that are incomplete (i.e., not mirroring all of the archive), incorrect, and outdated. You can find this in /debian/README.mirrors. Before you start displaying it from ftpd, I'll trim it down slightly. At the moment, there is an introductory paragraph or two that aren't necessary for this purpose. Please let me know where you'd like me to put this trimmed down version.