I had a very brief look at the App::perlbrew code. The perl- prefix relates to CPAN URLs, e.g. http://search.cpan.org/dist/perl-5.14.2/. I haven't dug any deeper than this but probably will do next week: there's still a few outstanding question marks.

I've successfully compiled 5.14.2 with threads and tested my frequently used apps. I skipped the alias step: it isn't strictly necessary and I want to find out a bit more about it anyway (e.g. I still don't know what the -f option does).

Thanks again for all your help with this.