In the case of my earlier posting, if there were other backups performed
during the day... he could just change the first letter prefix again.
  Say, "S" for special and "X" for X-tra special.

The intent was to keep it in the traditional MPE 8 character filename that
must start with a letter.

Besides there are 22 more letters besides the ones already used in my
earlier example.  How many backups do we want to do in a day?  Would he
need 100% auditability on all of them? :)