Many European vehicles are not imported to the USA because they will not meet the crash standards. The F-150 is about 500 pounds more than in the 70's to meet the higher crash standards that are in place now, and not 30 years ago.
There are many cars that got great mileage. I used to have a 83 Honda Civic, and it was really light vehicle, got around 30 MPG. Today the same car is going to be 500 pounds more, and larger 'more powerful' engine, that has higher crash standards.
Good luck finding something. I hope it works out for you.
Fred.