I think for the supermono it made sense to keep the weight down low.
For a scrambler... I'd put the horizontal head on the vertical cylinder move the plant up and forward in a shallow sump case.
I would use small end located piston, and just run balance on the flywheel... Harmonic damper or whatever.
The problem with the supermono design is width.
Have a look at one of the old singles. They are absurdly narrow.