I looked and never saw this asked or requested which surprises me.
There are many times, especially with a new DMX collection whose items need repeated tweaks and slight corrections, where I wish I could make edits to the entry (or even replace the file) without having the "Last Modfied" date change. Fix a typo, the LM date changes, and people think it's a whole new file when in fact they shouldn't even bother looking.
I do it now by editing the appropriate field in the database table, but that gets to be a pain.