Ray does not make an overdrive for the LT95, but he did mention that he was getting quite a bit of interest. If you ask him, and a lot of others ask him, he may spend the time and money to develop the OD for the LT95.
I did consider making an overdrive for the LT95 at one time but we have not done so for the following reasons.
AA It would be very expensive - virtually nothing in our existing parts bin could be used.
BB It is technically challenging. Because of the way the LT95 gearbox main shaft is secured with a retaining ring, limited space is available for the two concentric overdrive shafts at the radius of the mating gear. This forces design compromises that weaken the assembly.
CC. For most applications the 28% overdrive ratio usually supplied is way too high to be useful. My daily driver is a civilian 1984 Australian Isuzu 4BD1 powered 110 that has carried my wife and I on many expeditions in Africa, Europe and North America.
(The setup is very similar to the Parenties now being sold off in Australia). The engine does not have enough torque to sustain the overdrive ratio on an LT95 at 60mph on even moderate hills at sea level. Anyone making an overdrive has to do it primarily for the Parentie as it is the only significant market that still exists as far as LT95s are concerned.
IMHO most LT95 Land Rover vehicles would be happy with a 10 or 12% permanent increase in the gearing and this might be done by fitting alternative gears in the transfer case. No such ratio is currently available commercially for LT95 1:1 ratio 4BD1 vehicles but we might cut a set ourselves to see how practical this is.