Hello, After a discussion on a different thread, I came up with an implementation allowing containers to store and retrieve heterogenous instances, and provide correct deep cloning of those containers. A working motivational example is here http://tinyurl.com/larqyy. I have yet to do a comparison with container<boost::any>. This is just an initial proof-of-concept, and there remains a lot of work to do if it were to be a complete proposal. Before I did that work (especially since I have another proposal in the wings), I wanted to ask if there would be any interest in a completed system? The system is based on a modified ptr_container branch (also in the sandbox - I've contacted Thorsten about this), and and allocator adaptor system to deal with cloning. It allows one to place object pointers into a container using syntax such as: /// a vector of heterogenous objects template <class Alloc = std::allocator<char>, class Base = common_base > struct vector; heterogenous::vector<> v; v.push_back<T0>(); // add a default-constructed object of type T0 v.push_back<T1>(a0,a1,...,an); // add an object of type T1, passig a0..an as ctor arguments T1 &obj = v.ref_at<T1>(1); // get a reference of type T1& to the object at index 1 or throw bad_cast heterogenous::vector<> v2 = v; // copy the container; concrete types are preserved assert(v2.is_type_at<T1>(1)); There are many outstanding issues; it may not fly in the end, it may not work for all container types and semantics, but I would like some early opinion on whether it is even worth my pursuing further. One initial issue that may break any interest is that instances put into the container must be of a type T that derives from heterogenous::base<T>. Regards, Christian.