Gentlemen, Eric and Ynnos
I suspect that a small truck, like the famous Toyota that Top Gear tried to destroy would not be economical to build in America. as for imports, AFAIK the US government still has the very high tariff on such trucks that it introduced way back in the '80s (?) or '70s. ( I believe that there is a some weird thing that the Ford Transit Connect is actually imported with seats in the back so it can be called a CUV for that reason)
So a small truck might have to priced too high if built somewhere else... I don't know if the NAFTA agreement covers trucks.
Secondly, in the size range we are talking about, the EPA REALLY HATES DIESELS hence the lack of diesels available except from VW, BMW, MB and the huge things put in full size trucks.
For all that, it should be possible for, say, Toyota, to build their famous truck in Ontario with a good solid 2.5l 4 cyl gas engine from the Camry tuned for truck use with a reliable 5 speed or automatic at a reasonable price.