Im having difficulty finding a fix for this.

The machine is a Bomag MPH100R S# 86249U. The rotor has 2 Rotary Power units(hydraulic motors) on each side of the rotor assembly. One has a failed mechanical face seal and face plate which I have added pics of. I haven't been cleared by the customer to remove the unit (it would cost several thousand $'s for removal and installation) to get the ID plate specs which are inside the rotor drum. These units are obsolete to Bomag, so no help there. Rotary power is still building units, but cant identify the unit without the ID plate. I sent them these same pics this morning hoping that someone there may recognize them and be able to supply parts numbers. In the mean time, I am attempting a possible plan B. I can have the face plate repaired here, that's no problem. The big problem is the mechanical seal. The only hint I have is the ID of the seal is 7.5 inches. I was wondering if it would be possible to replace this with 1/2 of a duo cone seal like what would be in a final drive set-up. The problem is there isn't anywhere that I can just walk into that has 100's of these so I can attempt a possible match-up. Am I trying to do something impossible here? Plan C would be removing the unit which may have to take place.