Stumbled across this site today and thought about customizing a set of cards that might better fit for a 4 humors combat system.
http://www.artscow.com/photo-gifts/Playing-Cards
The custom round cards might also be interesting, especially if you created 4 quarter cards.
The Art of Game Design: A book of lenses
Jesse Schell
2008, 512 pages
from Cool Tools, in case you missed it: