> I'd be interested to see what features there are that
    > make the system slower in general, even when they
    > aren't being used. I did a lot of work in my PhD on
    > making odd features not affect the performance of
    > Ruby code when they aren't being used.

I suspect you would be warmly welcomed, and meet many interesting people, in the Perl6 IRC channel, especially if you lead to a link to your PhD.