http://www.carsthatmatter.com/blog/2008/05/classic-fuel-sippers/
Bearing in mind that most small-displacement sports cars from the 1960s and 1970s were pretty decent at fas mileage Cars That Matter put together a list of some of their favorites — most are capable of returning well over 20 mpg around town according to contemporary road tests. Click on the link for the full list, but I'm just posting the over 30 mpg ones
Austin-Healey Sprite — 36.0 mpg
Austin Mini Cooper S — 32.0 mpg
BMW Isetta — 44.0 mpg
Crosley Hot Shot — 48 mpg
Fiat 850 Spider — 38.5 mpg
Fiat X1/9 — 34.0 mpg
Honda S800 — 42.0 mpg
Lotus Elite — 38 mpg
MG Midget — 35.0 mpg
Morris Minor — 35.0 mpg
Nash Metropolitan — 37.5 mpg
Triumph Spitfire — 30.3 mpg
Volkswagen Beetle –30.0 mpg
Via: http://japanesenostalgiccar.com/blog/page/3/