In that case, the question should be, why am I attempting to convert one concrete type to another concrete type?

If you're writing a program, you should use the same type, std::vector<char* >, everywhere.

If you're writing a library, the API should avoid including container details in function parameters, and const and non-const T should be allowed.

    template<typename Container>
    void foo1(Container const& c);

    template<typename Iterator>
    void foo2(Iterator first);

    template<typename Iterator>
    void foo3(Iterator first, Iterator last);

    template<typename Iterator>
    void foo4(Iterator first, std::size_t num);

    template<typename T>
    void foo5(std::vector<T> const& vec);

    void foo6(char const* const* first, std::size_t num);

foo6 is a pretty good alternative here, imo:

    std::vector<char*> vec(...);
    foo6(&vec.front(), vec.size());

It would be cool if the compiler could figure templated type conversion out, but the crux of the issue is, as I understand it, that T<A> and T<A const> are not necessarily implemented the same way.

Also note that std::vector<std::string const> won't compile -- it wouldn't be copy-assignable -- so these issues mostly seem to arise specifically when dealing with C strings and/or C compatibility. And reinterpret_cast is amazingly helpful for porting from C.