I have a confession to make. I have considered something similar, not the melding of two vehicles, but transplanting a FXGT front end into an AW front. It would require a subframe, and some massaging of panels, and a humpy bonnet, but the tape measure tells me that it would fit. To avoid the gearbox synchronisation issue probably need to have an auto in one end and a manual in the other, or maybe two auto's?
Who's up for a challenge, who do I know with more doorstops than anyone else ? ? ?