Ford isn't the only global car maker than is under-supplying small cars to the US (a crime of which I recently accused Ford, which is stingy with the US Focus, not to mention downright missing in action with the Fiesta and Ka).
On my last trip to the United Kingdom I rented a Nissan Almera. I cruised the motorways at over 80 mph in this vehicle, a comfortable 4-door (with hatchback). And I got the equivalent of 40 mpg doing so (slightly less in town, but I reckon close to 37 mpg overall). I can think of no reason that you can't buy one of these today at your local Nissan dealer here in America.
BTW, remember to do the math when comparing UK and US mpg numbers. There are 160 fluid ounces in a British gallon versus 128in a US gallon. So when the Brits say a car gets 50 miles to the gallon over there, that's like 40 mpg over here.