Just watched Fifth Gear's feature on 7 seater MPVs getting rear ended by a lorry going 40mph.
http://fifthgear.five.tv/jsp/5gmain.jsp?mn...tion=Crash+Test
The results are not pretty. Some people comment that if the headrests were up, it wouldn't be that bad, though. I would think that hatchbacks like Jazz, Swift, Yaris, Aveo, etc wouldn't fare much better.