Advice on car rack for 4 bikes?

trek990
trek990 Posts: 11
edited September 2012 in Road buying advice
We are a family of 5 (boys aged 10, 7 and 5) and would like a rack for the adults and the 2 oldest boys, the younger boy's bike will be stuffed in the back of the car (a Mazda 5).
The Mrs rides a 700cc, Me and the 10 year old 26", the 7 year old a 20" and the youngest a 16".
The Mazda website doesn't give any recommendations for 4 bike carriers.
Ideally would prefer a rear carrier as we don't need a towbar.
Any advice? Thanks