I drive precisely just such a velociped! You'll notice that the EuroNCAP tests don't involve a rear impact on the car itself. (The whiplash tests are only conducted using seats mounted on a sled, out of the vehicle). Similarly, there is no mandatory rear impact test as part of European Type Approval.
As ever, the Germans are ahead of the game (at least their consumers are!) and have done exaclty what Botach proposes. (not pretty)!
http://motoren.wordpress.com/2011/02/22 ... of-an-mpv/Can't remember whether the USA requires rear impact tests but I don't think it does.
Obviously, rear impacts re less common than frontal or side impacts and, when you scratch the surface of those, they're are actually a fair few flaws in them compared to real life anyway. So you pays your money and you takes your choice. We don't use the third row of seats that often - usually when the kids bring too many friends home. Like everything else though, how safe do we want to be? How safe is "safe enough"? How much do we want to pay (not just purchase price but running costs and practicalities) for whatever level of safety we deem "sufficient"? Defensive driving still has to be the first line of defence I think. I love my old Alfa, but it has no airbags, seat belt pre-tensioners or Electronic Stability Control. If safety was my No. 1 priority, I wouldn't drive it!