bit like a motor bike you mean ?, or even a 2 seat F1 car dont know about anything that makes the cog higher for a 4 wheel drive that is designed for climbing over things at steep angles, it might work l will give it some thought
Baloo, yeah, exactly like that. How high up you put the passenger is obvioulsy dependent on how much room under their butt you need for diffs and suspension etc. As long as the passenger can see a bit over the drivers head/helmet then that's enough. COG would suffer a bit, but not that much as you can put the two seats quite close to each other.
Side-by-side would mean quite wide and as you say, engine placement can be difficult. Or you could do 2/3 of a McLaren F1 with the passenger slightly sideways almost behind the driver.
Another thought; Does the passenger have to face forward-ish?
Ideas, ideas...