Something that you may want to look into is becoming a full time DODDS (Elementary, Jr High, High School) teacher on one of the military installations. The pay is good and commensurate with the local economy (much more than the avg Okinawan). On top of this you may qualify for a housing allowance that equate to a pretty decent amount.
Also, there are colleges that service the military on each installation (Troy State, Central Texas College, University of Maryland Asian Division, etc). Seeking employment with them could very well turn out to be a much more realistic alternative to working in the Okinawan economy.