I think that there is a simple workaround that resolves some of the issues with syntax highlighting and the site. The solution involves adding to the standard PM CSS a set of attributes that cover the classes output by Perl::Tidy and a change in whether the 'DIV' and 'SPAN' tags are allowed by the site. (The last time i looked PerlTidy uses DIV and SPAN blocks with class info to do the highlighting.) This way people that want to post highlighted code will at least have the code renderable by PM, and that there will be the appropriate CSS to go along with it. Thus all they need to do is run perl2html on the code, and then paste it into their node.

Of course this means the CSS for each theme is adjusted and a bunch of other work, but at least its doable. At least I think it is. Maybe there is a good reason im overlooking that DIV and SPAN tags are prohibited by the site.