"sometime in the late 80's or early 90's Subaru did away with the dual-range manual transmission and a lot of the skid plate protection"
This has already been discussed in other threads, but Subaru still manufactures Outback and Legacy manuals with dual-range gearboxes. If Subaru does not manufacture them in the US for the US market, this does not mean that they don't exist, or that there is something preventing their fitment. Armed with this info, the advice I an offer is that (a) you get hold of a dual-range tranny from a non-US spec car, or (b) press SOA to make it available as an option, just as they do with LSD.
It is not surprising that the dual-range transmission is not available in the USA, as American drivers famously do not tend to go near the dirt, even in the biggest and toughtest of vehicles. Yes, it's a generalisation, and it does disadvantage those who are keen to use their Subarus' potential. Keep pressing the manufacturer, is all I can say.