I've posted a thread previously asking for recommendations for double pushchairs...I now need a bit more specific advice if poss? 
In June I need a double pushchair for our newborn and 1yr old DD.
I've done some initial research and seen a number of possibilities.
However, one requirement that I have is that I can put the baby's car seat onto the frame along with the seat for DD. I've found with DD that I've used our current pushchair in this mode a lot e.g if going shopping and DD falls asleep in car I often just pop the car seat onto the frame as I know it will be a fairly short trip.
At the moment the only double that I've seen that allows this option is the baby jogger city select (a bit pricey).
I was wondering if anybody knows of any other doubles which allows for this??
Thanks in advance