in reply to Interfacing Perl with C++, using XS, with external files, and using the STL as parameters and return values.

Your tenacity is to be admired. Thanks for documenting your quest.

Recently I pointed out the perl-xs implementation of google protocol buffers to tye. I dumped my scratch pad into a post: Protocol Buffers and XS

Perhaps you'll be interested to see how that project autogenerates XS around C++.