Odd numbers of bits was de rigeur in many customer processors, even DEC built PDPs ranging from 12 go 36 bits. And the bit-slice CPUs like the AMD 2900 family gave you whatever you wanted, in 4 bit increments.
“And the bit-slice CPUs like the AMD 2900 family gave you whatever you wanted, in 4 bit increments.”
These were used in Atari vector games like Red Baron, Battlezone, and Tempest :-). They were a hardware accelerator that handled all of the matrix math for scaling, zooming, and rotations while a 6502 ran the show :-).