There is an improved shell script and a data file containing a list of
slackware mirrors available at

ftp://andthatsjazz.org/pub/slackchange.tgz

slackchange.sh lists the size of ChangeLog.txt for each mirror and
indicates whether or not rsync is available from that site. It
ignores any site that does not provide anonymous FTP unless it instead
provides rsync.

Beware unusually large ChangeLog.txt files. Empty files suggest
further investigation (and possibly correction to slackware.com's
mirror list if the site is fast and near).
--
buck