I think something like this would be great! A group of us (me, Seth Pollak, Dave Sobel) were thinking of something along these lines, though, perhaps we have been less focused on changes with age and more about what we are calling an “integrative” view. We think that a real challenge facing cog dev folks is that although we acknowledge the value of multiple intellectual and theoretical orientations (i.e., socio-cultural, cognitive diagnosis, neurobiological) integrating among these at any point in the study of children’s development is rare, partly because it is so difficult (different methods, different assumptions, different language, etc.) We imagined that a special-topics conference on children’s learning (like the one you’re suggesting) might take as at least one of its goals a discussion of ways in which our science might benefit from a truly integrated approach to understanding learning, and how we might begin to take some steps toward that.
We cobbled together a proposal that we could share, but thought it would be best to add in here as a start!