Without sound too po-faced about it, I like this idea but I think it'll miss the humour and referential nature of mash-up music. For instance, one of the best things I've heard (that I've never manage to hunt down) was Hexstatic turning the theme from Hitchhikers Guide to the Galaxy into a somewhat stomping dance tune, whilst projecting elements from the end of 2001 onto a massive screen, interspersed with "Don't Panic" written in large friendly letters.
That's not just about finding two pieces of audio that fit well together: it's about meshing cultural references (that will be particularly meaningful for someone of my age or thereabouts) into something new. This reminds me of a comment from Harry Allen:
"Hip hop is massively hypertextual, which is the reason I started this journey. There is a huge dialog within the hip hop culture, in which artists strike references to other artists, other records, news events, cartoons, TV shows, advertising, imagery, words, infiections, sounds, ideas, and concepts of all kinds. "