Well what you do hoagie is you actually TRY the new version out before you put it on your mame cab. If something important to you isn't working then you wait.
Actually lazarus doesn't support multiple versions of mame.... Well it does but your gamelists would have doubled entries, one for mame and one for mameb or whatever it's called.
On the other hand 3darcade does. You toggle a button and it launches the alternate mame you specified instead of the main.
I could add this feature, but I don't find it particularly useful.
Someday, however, I might add it to the listgen's features if it's a slow day.