Through Distro Watch I found a link to Mirror Watch, which posts the sites a distro is available and how current it is. Now that the feeding frenzy is over for 3.4 it may not be necessary, but it is a clean site which shows which mirrrors are current.
http://www.acert.pt/~fribeiro/mirrorwatch/?id=11

The id=11 is for KNOPPIX, which was recently added.