I have thought for fun about a little RISC microcomputer with 6-bit bytes, and 4-byte words (12 MiB of addressable RAM). I think 6-bit bytes would have been great at a point in history, and in something crazy fun like Minecraft. (It's actually interesting question, if we were to design early microprocessors with today's knowledge of HW methods, things like RISC, caches or pipelining, what would we do differently?)