The Rubicon NVG241OR is not in the same series as the NVG331-J. The NVG241 is overall 150% larger. It would be a waste to chop up the stronger 241 and keep the 231 as the transfer case.
i have a D300 but seems that the adapter is more expensive than i thought so it won't be happening anyway. My thinking was to get a rubi case with the case busted to use the planetary reduction gears out of it.