there is a quad pram you can get! Its around $1300 i think new. It has twins side by side and newborns fit on top. Hard to explain, but it is exaclty for your friends senario. If you look on the AMBA web site- they have a shop and there are pics of it there! IF you cant find the pram still, yell out and i will PM more details to you!

i have know a few friends in a similar predicament through twins club and my SIL has 2 sets , a singleton and another on the way- all under the age of 6 years!

HTH
odette