Lionel made a number of traditional GP-9s with twin can motors. Only about 4 of them, though, all Chinese production. I have the C&O version, which came with a set, and plan to use it with another shell. There were three different shell mounting types going back to the 1970s MPC days, but your B&M engines have the most recent 4-screw type, with the screws going in from the bottom of each corner of the chassis into plastic shafts coming down from the shell. The twin can motored versions use the same mounting system. Thus, it should be relatively easy to put the B&M shell onto the can motor chassis.
Your primary issue will be the second powered unit, because I don't think the AC Pullmor motored engine is going to play well with the DC can motored unit. I think I would just buy a dummy engine to get the chassis, or buy one of the dummy B GP-9 units Lionel made, and use that chassis, and put the other B&M shell on that. That twin can motored engine will have plenty of power for what you're going to use it for, so you only need one powered unit.
