I wonder if those import pickups will meet USA emission standards? As a side note, I don't think I've ever seen as many small double cab (4-door or crewcab) pickups as I saw in Bonaire. It seems that is all they rent to divers, and the do work great. Most even come with a tank rack in the back. But all I saw were gasoline, not diesel powered.
You got to be kidding in regards to emissions. Those diesels are WAY cleaner then most of the gas engines currently on the market in US, just look at the TDI Jettas from VW or 325TDS from BMW, those cars have no problem passing emission testing in EU though the standards increased a couple of times since their initial production date. By the way, a mazda 323 diesel was at some point available in Europe, it would burn 4.5l/100km, that equals to 1.3g/60m or 40+ miles a gallon and believe me that car was flying faster then most of us can handle; it had no trouble maintaining a steady 140km/hr; now the fact that it was a manual and you needed to take care of it like put in it proper diesel with proper additives depending on the season is a different story. If US GOV would have any concern whatsoever in regards to the carbon footprint all they have to do is limit the use of automatic gearboxes to cars for physically disabled and such, that adds at least 4-5 mpg to ANY car I know of, but, on the other hand the retards drinking HOT DD coffee and eating PapaGino's pizza while painting their nails or reading the newspaper on the highway would become even more dangerous.
I tow a 1500 pound sailboat + gear + weight of a trailer with a regular inline 4 Tacoma, manual transmission, standard 3 seat cab 2 wheel drive; it does just fine as long as you use 5th gear only when you exceed 70mph (I know, I have a speed obsession) and it still gets GREAT gas mileage compared to a regular american car with nothing in tow.
On the other hand, if I ever get a heavier boat package I would not use the Tacoma except for short non highway runs.
It's not the engine you have to worry about in a tow truck, for that you have the gearbox and a PROPER cooling system on your engine (most of the modern engines will handle 3500-4000 rpm ranges for their entire life with no ill effect and thats in excess of 100mph in 4th gear of a Tacoma), it's the braking power, if you can't stop something you should not even TRY to hook it, forget about towing it on the highway.
If you end up buying a rear wheel drive I would advise to load you gear in the truck, I mean EVERYTHING that you can fit or at least the heaviest of it, get a braking system on the trailer and be careful how close you get to the guy in front of you.