Here is the problem: A tuple or variant needs to be defined, whose types are derived from an mpl::list (or other model of MPL Sequence). How is it to be done? I have considered that I might be able to define the tuple/variant with the types and then generate the sequence from there, but that still leaves me wondering how to define another tuple/variant with a sub- or super-set of the types in the generated sequence. Consider that I am supplied with a sequence of types, and that I want to define either 1)a tuple of pointers to them, or 2)a variant based on those types as well as pointers to them. I have considered that it would be a good thing to provide sequence-based tuples/variants and still provide the current variadic template (<--is that the correct term?) versions--which could be implemented in terms of the sequence-based ones (in my uneducated opinion). But I wonder if there is another solution already available which I have not considered. TIA for your consideration, Brian