Not what I am seeing. There are no links, even if I hoover with the mouse over the numbers inside the cells (I'm looking at the pdf with adobe reader 9.1).
In short, PDF::Table doesn't have a "cell_render_hook". This is a
patch I suggested in response to the original question.
In other words, without the patch you of course don't get any links,
as they're being generated within that callback function...