Earlier, I was looking for a way of managing my "About Me" boxes across the different SE sites. Seems like the features are not available at this time. I'd like to suggest a new way of managing user's profiles across the sites.
It makes sense to arrange the user's profiles, and specifically the "About Me" box, in groups as well. Thus, all programming sites share one profile with programming related description and all science sites will share a different profile.
I think that an improved feature for profile management would be an option to sync a profile field in a site with the same field on any other site. For a coarser granularity, syncing the whole profile is almost as good, and requires storing far less interconnect information.
Further improving it would be to make the fields/profiles linked together rather than just sync on demand. This way, changing a field in any one of the grouped sites will have immediate effect on all linked-to profiles on the other sites in the group.