Do you like the BJCMD fold? Or would you prefer a traditional umbrella fold? Ideas that come to my mind:
Downsizing to a single BJCM
Valco Snap or Snap 4 (four wheels, similar fold to BJCM)
Cybex Onyx (or Ruby if you don't need a full recline)
Baby Jogger Vue (not released yet)
I think I remember reading in other threads that your littlest likes to be worn, or needs to see you at all times...if I'm remembering correct and I was in your shoes, I'd wait for the Baby Jogger Vue. It really looks like an awesome design and you could easily transform it from a parent facing umbrella for the little guy to a front facing when your older needs a ride.
Here's a link to Baby Gizmo's review on Youtube:
[ame="http://www.youtube.com/watch?v=HfBGE3VmEzk"]Baby Jogger Vue Lightweight Stroller Review by Baby Gizmo - YouTube[/ame]
ETA: If you decide you want something more "full featured", but still lighweight and can spend a little more, you might want to look at the Ingelsina Avio or new for 2014 Trilogy. The Trilogy will have a reversible seat as well.