desktop magnifying glass

Got a question for you modellers out there (and this is pretty
much only applicable to those who use or know of what I'm looking
for) - where would one get one of those large magnifying glasses
that you mount on a desk for miniatures work? (or other teeny
applications)  Not entirely sure where to look, but I did try
a couple local hobby stores I know of, but nada.

A lighted one would sweet, but any at all would be helpful (you see,
I want to paint serial numbers on the rivets on my DS miniatures  ;-)
;-)

Mk