Hi Justin -
Apologies for the delay getting back to you.
My bias would be to keep the talks focused on platform agnostic topics, for the most part. However, you did mention using C++ smart pointers to make Win32 less painful. I think there could be some potential there, demonstrating how to use the more advanced features of C++11 smart pointers to simplify integration with 'unfriendly' APIs. I'm not sure how widely known such techniques are, and those techniques aren't MS specific.
As far as COM, is that still a relevant part of the Windows development environment? I remember it being quite important many years ago, but I thought that CLR had obviated the need for it? On the other hand, acquiring an understanding of the design of COM is certainly good for anyone who wants a deeper understanding of the C++ object model. If it is still relevant, perhaps it could be presented in a way that limited its Win32 specificity?
Would you be interested in giving a presentation along these lines?