I am working for the past 2 years on a java port of mame emulator (arcadeflex) based on old mame 0.36 src
I have succesfully ported a number of drivers (most noticeable - pang , double dragon , pkladies , 1942 )
source is available in github
If anyone interesting on helping just drop a note . Looking for help mostly in sound part (none of the drivers has sound yet)