Does any software out there actually use the modfied file list? I am
wondering if it can be used to speed up my incremental backups.

Here is my situation:

I have a volume with about 57GB. It has a little over 2.5 million files on
the volume.

Constantly new files are being added to this volume at about a rate of
10000 files a day.

When I do an incremental backup it takes more than an hour as the bakup
software traverses all of the folders that have already been backed up
before it actually gets to the new data. The actual data backup takes less
time than the inital scanning of the folders.