I agree also that we should provide a way to build Boost with CMake.
There is guy named Ruslan Baratov that runs a kick-ass-CMake-based package manager called hunter that integrates the build of Boost with CMake. If you have not checked it out, then it is well worth paying a visit to the Boost page on the wiki:
It is not a pure CMake build, but it is well integrated to the point that you won't really need one unless you have very specific needs. It takes the CMake toolchain configuration into account to build it, as an example of the integration it provides.