We've just bought an Alfa Romeo 159 sportwagon
http://gomotors.net/pics/Alfa%20Rome...rtwagon-05.jpg
It fits a maxi cosi car seat with base for baby, a big high back booster and then a small booster cushion. There are other cars that would be better but hubby really wanted it :rolleyes:
The cars we found with the most room were Range Rovers (pretty much all of them), Volvo V70, XC90, XC60, S40. Honda FRV. Opel/Vauxhall Insignia.
We struggled with BMW 5 series as the middle seat is really narrow.
I found a good website which did tests but it was Australian so didn't have many European cars. I'll try to find it again.
We went to a large car supermarket armed with the maxi cosi, booster and cushion, then just went from car to car!