OKA are back up and manufacturing again now (mainly as built to order) and will also "remanufacture" existing OKA's from the "old" company that went belly up.
The current ones are using a 4 cylinder Cummins mated to a 6 speed Allison box, Dana diffs.
GVM of 6.5 ton, 36 inch tyres stock

...but at $150,000 G's for a single cab-chassis there is a lot of competition in that price range