I spend most of my time on TGO reading old threads rather than posting, and I've been captivated by this subject. Or topic. I see these options: (1) Accept that these cars are RWD and buy an AWD in addition to or instead of a third gen. (2) Try to adapt a lot of Subaru / Audi / etc parts. (3) Try to adapt an AWD Astro / Safari subframe. (4) Custom tubular crossmember with FWD GM car hubs, knuckles, etc and an S-10 front differential assembly. You can probably figure out your own (5).
So moving from technical implementation, the underlying concern is the reason for considering it. I ruled out snow because why risk crashing such an investment? Racing? Nose-heavy isn't a winning formula, and if none of the already available options checks all the boxes on your list, you probably need a tube-chassis custom, then try to fit a body to it. Off-reading? No way, the front overhang is too long, the wheelwells are too small, the view of the trail directly ahead is blocked by the seating position as much as the length and curve of the hood. I couldn't come up with any legitimate reason beyond the technical challenge itself.
The metal fabrication skills are out there in abundance. The parts selection abounds also. Which leaves it being a mental exercise. Intriguing to consider for a little while, but not worth pursuing.
Why bother posting this? Because I can't claim to have considered everything, and if not, I hope to learn from any considered replies.

 

P.S. Thinking about Summit's old QuadraDeuce AWD '32 Ford, and the Sy/Ty, nose-heavy is probably not so bad for AWD acceleration

 

I helped with 2 AWD vehicles that were built in Poland. The first was a Typhoon, which was not a big challenge as far as setting up the AWD, and the second was a mid '70 Corvette, which was more of a challenge. I didn't have anything to do with the fabrication of these vehicles, but I did build the front and rear differentials for them. Traction is a big problem in Europe because they don't have any dedicated drag strips over there. They run on airport runways. AWD is a big advantage for the faster cars over there. The Typhoon was the quickest car in Europe at the time until the Corvette was finished. Then the Corvette was the quickest for about 6 years. Both of these were running turbocharged small block Chevys with 12 bolt rear ends and S10 front differentials.

 

Any pictures you can share with us of the Corvette?

 

There's one famous Syclone from Iceland or Northern Europe, I never understood why he kept the 7.25" front rather than swapping the 9.25" from a K3500? Aside from the obvious strength, there are air lockers, E- lockers, lunchbox lockers, and Truetracs available for them. The 7.25 has nothing, there was a LockRight, but it broke the cases. The PhantomGrip is a bad joke that never works well, and never lasts long. There are a few iron cases for the 7.25, but they are too rare for Powertrax to bring back the LockRight.

 

These are the only pictures that I have, but if you go to yotube and search VTG Corvette you will see a lot of videos of it.