I have been looking at this same idea. I have a S-280 shelter now and am loving it. So much so that I am tinkering with the idea to get a M1082 or M1095 to keep a second one on. Some of the things I found that I liked was the M1082 was rated at 5000lbs offroad but weighs a bit over 6000 lbs empty.
The M1095 was dual axle and is rated at 10,000 lbs but weighs 9200 lbs empty.
The cargo size on the M1095 is a bit longer 168.8" over 148.8" on the M1082. A S-280 shelter is 147" so it would fit in either trailer.
Both work on air brakes that are compatible with the M809 series trucks and can run the same size tires you can run on your M809 although LMTV style wheels are not exactly the same as our Combat or HEMTT wheels, I have forgotten that detail. But I was thinking to get a M1095 and put 4 16.00R20 wheels on it giving me 12 total tires, 8 rolling and 2 spares. (I have 8 tires now and would be adding 4 with a trailer)
At near 6K/10k of weight and a serious amount of length either trailer a would not make our rigs very mountain trail compatible, so as it is, I am attempting to keep all my plans on just my M813 and if a nice trailer or another S-280 happen to come my way then all the better.
On another note I saw a M923 that had made a 5th wheel hitch off the back. When I asked about it the MV owner said it bolts right to the same pintal hitch location and swoops upward to the right height for the connection to sit on. Was a very interesting mod. He had made it a bolt on device so he could switch back and forth from pintal to 5th wheel if he wished. I tried to find the video where I saw it but had no luck.