I came across this interesting article
Colizoli O, Murre JM, and Rouw R (2012). Pseudo-Synesthesia through Reading Books with Colored Letters. PloS one, 7 (6) PMID: 22761905
posted at http://neuroskeptic.blogspot.com/2012/07/can-you-learn-to-be-synaesthetic.html
I agree with the blogger and some real syn-esthetics who commented that it really has little to do with synesthesia, and more with mnemotechnic. I wonder if it could be used to learn Chinese characters.