I definitely don't think it can be split into three levels... and after a certain point, Perl skill doesn't even fit into coherent levels, as people become specialised in certain areas.

I think the great thing about Perl (and maybe programming in general) is that the more you learn, the more you realise there is to learn. In that sense, the whole 'Monk' analogy is very apt. True mastery takes a lifetime (or more).