I got the Sharp ROM 1.40JP working now on my SL-C760. I used the updater.sh file for the 760 from the page for Testu's kernel updates.
Everything appears to work great. I did notice that qtmail 2.42 produces a number of error messages when run from the console. Otherwise, it is functional. The errors appear to be related to SDL, such as QPaintDevice and QPixmap. From time to time, it has problems displaying the pencil (compose) icon. I checked the pic files, so I think it is more a problem with rendering.
Many thanks!