One-ton pickups? You mean like the F350? They've had diesels in medium-sized trucks(F250/2500/etc) since the 80's, and still have them.
That being said, if you want a new truck with a diesel and a stick, you have to go with a Ram.
Anyway, I agree on the bullshit regs; they are just trying to prevent most from going with Diesel.
Why? I'm thinking it's so the flow of gasoline can be restricted if needed without impacting all of the commercial rigs, which are all diesel.