Another +1 for E39 BMWs.
Would drive my mum's one for any distance. 96 528i with 133km did 6.6L/100km with ac on cruise set on 100kmh for at trip I did. (1600rpm @ 100kmh)
A full tank at that consumption is around 1000km..
http://www.carsales.com.au/private/details/bmw-523i-1997-12697454?base=1216&vertical=Car&cr=4&eapi=2&__N=1216%204294729575%201246%201247%201252%201282%204294967079%204294966837%20900&silo=Stock&Range=Price:Min,20000~1&sort=default
Edit: I've also had a 540i and took that to the track on a 40deg day. Was totally perfect and I gave up before the car did...
http://www.carsales.com.au/private/details/bmw-540i-1998-12825350?base=1216&vertical=Car&cr=1&eapi=2&__N=1216%204294729575%201246%201247%201252%201282%204294967079%204294966846%20900&silo=Stock&Range=Price:Min,20000~1&sort=default