[s-cars] NAC - Why is manual and full-time 4wd or AWD mutually exclusive in SUVs

[Edward]

Hello all,
Very unrelated to UrS, but I am trying to find a high-clearance vehicle to
tackle water bars so I can stop abusing my poor 95 S6...

Much research has landed me the conclusion that the few high-clearance
vehicles available with a manual (xterra, for instance) are part-time 4wd
only.  Vehicles that in the recent past offered full-time 4wd or AWD and a
manual (pathfinder, 4runner, explorer) only offer part-time with the
manual.  (I'm looking at SUVs of this nature as vehicles like all-road and
outback, while higher clearance than a car, do not really offer enough
approach angle to actually clear the average BC water bar...)

Is there some challenging technical reason for this that audi & subaru have
overcome to get AWD and manual in their cars that doesn't scale to a bigger
vehicle?  Or is this just a function of market?  Am I only one who wants a
manual and on-dry-road 4wd?  Is there some vehicle I'm missing?

Found myself curious and unable to solve on google... figured someone here
*must* know!

Thanks (and sorry for the NAC question),

Ed