Now I have a dumb question. Why would you want a High low, or a low high?
Gearing options.
You would have highway gears - high, high (same as high range).
You would have back road/off road gears - low, high (same as low range).
You would have crawling gears - low, low (twice as low as low range).
If one of the boxes has a different low range (usually about twice as low) then you would have:
high, high - highway
low, high - back road
high, low (lower set of gears) - crawling
low, low - serious low speed crawling
Because Suzuki Trackers/Kickers have a single gearbox&transfer case (one unit) making duals is difficult. Also as the gear boxes are stacked together the drive train gets longer and the driveline has to be shortened, increasing the angle it has to run. When the angle get to much equipment starts breaking. Two door rigs do not have much space to start with. Samurai's, LJ's, and SJ's have divorced transfer cases with a short driveline between transmission and TC. You can see that shortening/eliminating/combining/stacking should all work to get duals. Toyota TC gear boxes can be bolted together with adapters to stack them in a more ridged reliable manner.