As far as an OSS "Graffiti", I have come across it in the NDS homebrew world. Not sure how useful it will be, but binaries and source are here:

http://gugusse.central.free.fr/papaf...Frotz_v1.5.zip

I'm sure you can make a few small changes to the alphabet if it keeps you out of trouble

EDIT: Here's the main page, scroll way to the bottom to see the input method. Thanks again.
http://gugusse.central.free.fr/papafuji/adventures.html