Are you aware of the modularization plan for boost?
https://svn.boost.org/trac/boost/wiki/CMakeModularizationStatus I'm aware now :). I have seen Jens Weller's Boost dependency analyzer ( http://www.meetingcpp.com/index.php/br/items/boost-dependency-analyzer.html ) and I was pretty sure that it was related to efforts like this.
Note also that even with code in separate git repos, there is currently a complex mesh of interdependencies between the repos/libraries. The real work is to do actual modularization of the code: I think that the modularization effort has a lot of value. I don't think it is necessary for NuGet though. As I understand the modularization effort, it is also trying to express the dependencies between headers-only libraries. For NuGet, I would likely just put all the headers in a "boost_includes" package. Sergey has already demonstrated that such an approach is possible.
That said, Google hasn't shown me any documentation on binary-library dependencies. This can be determined empirically, but I am afraid of the information getting stale.