Kirjava
Colourful
I hear that OLL/PLL has potential, too.
Have you already a rule for:
What is 'correct' corner permutation after doing a 2x2x2?
What moves are allowed to extend the 2x2x2 to a 2x2x3, while preserving correct corner permutation ?
P.S. Cool answers to this questions will make for a new ZZ-d style 2x2x2 method.