I have to laugh when owners analyze their gas mileage these days and think that modern technology and engine gizmos is all that can lower fuel mileage. Not you guys, but in general....the "green cars" really have nothing on some 40 year old classics!
What can really lower fuel mileage is ridding cars of all of the "dead weight" and "luxury" that is built into cars today. I know safety item like multiple air bags doesn't make a car any lighter either, but we do need safety.
I have a 1973 BMW 2002tii with Kugelfischer mechanical fuel injection. It is bone stock and on long journeys to car gatherings when I am flying along at 80mph this car can easily get 33mpg, and the smile on my face isn't from the great fuel mileage!!!
Oh, and it does have safety belts, but they don't weight very much. So a 2.0 liter BMW mechanical fuel injection engine that puts out about 130hp, with a 4 speed and 2.73 non-ls differential that weighs in at probably 2500 lbs "with driver" can get still get it done!
That being said, this is one reason I am finally buying my first MINI...I'm sure my smile will be just as wide, if not wider.
To the OP, if I had the opportunity to buy a family car with 4 doors on a MINI platform, like you can today, I'd be so absolutely elated I wouldn't worry about mileage...just enjoy the total package and be glad you didn't have to cart your family around in a 2 ton box like a "van" or something!
Cheers,
John