Pete Larsen used a trailing arm (from a Honda Goldwing I think) for the rear tire's engineering. This avoided the future M3W's Bevel Box issues but made the right hand seat smaller and wedge shaped; would have never been marketable as a RHD that way IMO. In the US, where butts are too big, and we would sit on the larger left seat, this was probably a good thing; passenger just needs a tiny 'pizza shaped' rear!
Hmmmm, how would my wife react to a second expensive and impractical toy? "But honey, I WAS a good boy this year and Santa brought IT to ME; not my fault, I swear!"
I think she might swear too!!!
Here is a side by...