The problem that I can see in this proposal (but I must confess that I'm in a hurry..so I've read and reply quickly):
You tell:
#Rom List
nbajamte.zip "NBA Jam TE (Rev 4.0 03/23/94)"
rom2example "Rom2Example (world)"
rom3example "Rom3Example (world)"
rom4example "Rom4Example (world)"
What I see:
1) The problem is that the Rom name may often change from one version to another!! So if you associate a game rom to a 'modified' description when the rom game name will change it won't be linked to anything anymore..or worst, to another rom!
2) The favorite list is based on the 'Official' description of the game (which, as far as I know, do NOT change over time). That allows to update your roms set without losing your favorite list! Indeed, this list is based on the description (which doesn't change over time) and link to the rom name, even if it has changed over time!
So, once again, on a new mame version it would be difficult to associate your 'modified' description to the new rom name.
Hope that I'm clear and that we are talking of the same think ;-)