#include <new>
#include <type_traits>
template<typename T, typename... V> void reuse_inplace(T& obj, V... args)
{
    static_assert(!std::is_const<T>::value, "in-place construction over a const object");
    obj.~T(); new(&obj) T(args...);
};

Nice. I'll switch to this once I move to VC++2013, as 2012 doesn't support variadic templates.