Back in the late '70s, I recall running across fleets of small pickups with
small diesel engines in them (Nissan, Tohatsu, Isuzu, etc).  All I saw were
stick shift, and got phenomenal road fuel mileage.  Although small, they
were sprung like a billy goat (really stiff suspensions), and could carry a
pretty good load without instability.

A few people around the US were running around in fancier versions of these,
sold through dealerships.

Are there any modern day counterparts to these available at dealerships?
If so, what brands would I look for?