I bet on the BMW R18 engine...
That would seem like quite an enticing option, assuming MMC go down the BMW parts-bin route.
![[Linked Image]](https://www.tm-img.com/images/2020/12/03/R18-3.jpg)
It's compact engine and gearbox would allow for some neat packaging while retaining something bright and shiny sticking out the front of the car. Not a V-Twin but better than a front wheel drive Mini engine hidden under the bodywork somewhere. It seems that the R18 gearbox has a reverse gear too!