I'm one of the tossers Clutch hates, I would like an extra 100 or 150 miles from my fuel tank. I hate jerry cans ever since one leaked camping and I had to spend 2 damn weeks (doing the Toroweap trip) with the smell of gasoline permeating everything in the WilderNest. Screw that, I don't keep gas inside the truck anymore and don't (and basically won't, at least anytime soon) have a swing-out rear bumper. So they sit on the roof rack that I have to put on just to carry the fuel that should be nice and safe in a tank designed to carry it under the truck. It's a load of crap that we don't get diesels and aux or long range fuel tank options on our trucks.
BTW, that McDonald's things is a stupid measurement. It assumes you're getting 15 MPG in 2WD high on nice highways. You might only be less than a tank-full away from a town if you data mine a map sitting your house in San Francisco but say you're in the Needles District (which Mr. Von Worley probably never heard, being in the middle of flyover country) you'll need that extra 10 gallons or the MPG of a rattling diesel. I'll repeat until I'm cold and dead, I don't want a diesel to pull junk or go 900 miles between Interstate stops. I want one to bounce around backroads without worrying that my 1GR is getting 6 MPG. A 19 gallon Toyota pickup tank gets you (say) 475 miles with a D-4D on pavement (assuming 25 MPG) and not all that much less in low range.