Based on code + help from Alex Stapleton:
*Add Eigen/StdVector header.
Including it #includes<vector> and "Core" and generates a partial
specialization of std::vector<T> for T=Eigen::Matrix<...>
that will work even with vectorizable fixed-size Eigen types
(working around a design issue in the c++ STL)
*Add unit-test

CCMAIL: alex.stapleton@gmail.com