There's an amazing amount of skill residing out there in home workshops, a great example is this BMW with a 694cc homemade cross plane V8 engine from two inline fours. According to the builder, the crankcase was machined out of a solid piece of aluminum and he machined his own cross plane crankshaft. He made new cams because the timing was wrong for a V8 and he reversed the rotation of one of the cams. Looks like Honda CB350 top ends.
I'll see if I can get more information but the videos are included below, the first run and then installed in the bike. Sounds good, doesn't it?
Thanks for the tip, Matt!