monitor a series of files for absolute size (alert & trending)

greetings,

I need to monitor some os and db backup files for their sizes for alert
based on absolute sizes as well as rrd trending. Does Hobbit do this now? I
am running 4.2-RC-20060712 on CentOS 4.3/i386.

A twist is the file names are timestamped (os-backup-YYYYMMDD-HHmm.star.gz).
any suggestions/tricks? I thought of making a copy to a fixed name for
monitoring, but it is kinda expensive due to the size of the backups
themselves.