I have considered the same it is feasible! allot of work and new things to mitigate.Not direct drive. That had not not even occurred to me. My thought was inverted with a gearbox. I like the engine in the vertical orientation, and my project is pretty narrow. Upright with a tall gearbox would be ideal but such a thing does not exist.
I found this guy who converted his to a dry sump, but that might not be necessary with redesigned valve cover.