Have you considered using the modules Tie-IxHash along with Digest::MD5 to fingerprint whatever your checksums are checking now? This combo may give you more leverage than rolling your own sorted order hashes and checksums? Just a thought!

By the way, you are personally invited to the next meeting of the DC Perl Mongers. See http://dc.pm.org for info if you're interested. I've read many of your nodes here in the Monastery and would like to meet you in person someday!