A competent fabricator could probably swap in the transfer case, front differential, and front suspension from a Cadillac SRX with AWD (I happen to own one).
Not trivial but possible.
I saw an old (50's) Chevy P/U with an old Oldsmobile Toronado drivetrain and a dual rear axle setup (two (trailer) axles with a single wheel on each end) with appropriate rear fender revisions in Cedar City, UT one morning ~ 20 yr ago. I have a pic somewhere.
American Folk Art at it's best.