I don't now about the cranks, but I do know that Campy has a 12-29 cassette for 11-speeds now. My home terrain is like Hill Country -- short (by mountain-speak) rollers that I can use my 39/26 for if I want. If you put a compact crank on that your low gear is effectively a standard triple of 30-26.

When I travel, I use a triple with a 30/29. Yep, super-granny. But, if I wake up tired or ill I want a gear that I can spin comfortably up to an 8% or so. I like knowing it is there.

But, I'm surprised how much I will use the 39/29. That extra 3 cogs isn't much but, for me, it seems to be just the little oomph I need.