Object factory in C++11

A constructor arguments caching object factory. Implementing it from scratch may be a good interview question for RVO, rvalue references, move semantics and smart pointers in C++11.
#include <memory>
#include <functional>
#include <utility>

#include <boost/functional/factory.hpp>

struct manufacturable {
    virtual ~manufacturable() {};
    virtual void api_method() const = 0;
};
using manufacturable_ptr = std::shared_ptr<struct manufacturable>;

struct factory {
    virtual ~factory() {}
    virtual manufacturable_ptr create() const = 0;
};
using factory_ptr = std::shared_ptr<struct factory>;

template <class T, class... Args>
struct factory_tpl final: factory
{
    std::function<std::shared_ptr<T>()> impl_;
    factory_tpl(Args&&... args):
        impl_(std::bind(boost::factory<std::shared_ptr<T>>(), std::forward<Args>(args)...))
    {}

    virtual manufacturable_ptr make() const override { return std::dynamic_pointer_cast<struct manufacturable>(impl_()); }
};

template <class T, class... Args>
factory_ptr make_factory(Args&&... args)
{
    return std::dynamic_pointer_cast<struct factory>(std::make_shared< factory_tpl<T, Args...> >(std::forward<Args>(args)...));
}

struct concrete_manufacturable final: manufacturable
{
    std::string const domain_;
    concrete_manufacturable(std::string const& id): domain_(domain) {}
    virtual void api_method() const override {}
}

int main()
{
    factory_ptr factory = make_factory<concrete_manufacturable>("demo");
    manufacturable_ptr object = factory->make();
    object->api_method();
    return 0;
}