More than likely, it could be said that there is just too much work involved in trying to make a '72 'stang look like an XB. While the hood scoops and front bumper designs look a lot alike, that's about where the similarities end. The body lines are actually very different. For some pretty good reference pics, see here:
Styling - Bonnets
'70-'71 Torino could [arguably] be considered closer, but EXTENSIVE work would still need to be done with the front end--you'd likely not be able to use ANY of the original sheetmetal.
The body lines of the '70-'71 Maverick are also actually very similar--especially from side profile--but just a bit too "compact." With some fiberglass work to reshape the body lines around the bottom of the quarter windows and the rear decklid, a Maverick could be made to look a heckuva lot more like a "short-wheelbase Falcon XB."
I'm actually surprised no-one [in the US] has ever tried to use a 4-door Maverick to make a Yellow MFP Interceptor replica...
P.S. just re-read your post and realized I've got your intent completely BACKWARDS. Mea culpa...