I saw your post looking for a Nikon lens for your 12x20. As I said to Mat when he showed us the 360mm Schneider he had gotten, I am so envious; A: that you have gotten it and B: that you can still carry it. I am considering mounting tandem wheels on the baby jogger, but I would still have to put it in the baby jogger.
I'm considering a baby jogger myself, actually. I estimate all the gear is 60+ pounds (with 1 lens!) I don't think I'll be backpacking with this beast.