Anyone not had a toddler seat on their pram for their toddler?

[MummyTummy]

At the moment I am looking at prams and have narrowed it down to two. The Baby Jogger City Select and the Bugaboo Chameleon.

I have pros and cons for each of the prams - as far as I am concerned there is no perfect pram out there for me!!

But a big difference is that one pram has the doubles capabilities and the other does not. I carried my DS around in a sling mainly for the first 6 months or so, and then still preferred to use the sling for shorter trips until DS was around 10 or so months. So I figure that I can still possibly get away with the single pram, but it only has the skateboard attachment and DS is really just too young to ride it effectively for quite some time (he will be 21 months when this bub is born). So only 2.5 ish by the time I need to put new bub in the pram......

I want to know if anyone has persevered with this sort of arrangement for their two kids?