I wouldn't brew a dunkel with Pilsner or light extract. The base malt for a dunkel is Munic malt. If you use Pilsner and try to get the color only with specialty grains, you will get a roasty flavor, which I find out of place in almost any German beer style.
Munic malt can be replaced with Amber malt extract. Add a little (0.5 lb) Cara Munic II (dark crystal), some Carafa Special (dehusked roasted malt). Aim for about 12-13*P and hop to about 25 IBU with one bittering addition of German hops.
If you want to do a mini mash, add 1-2 lb of dark Munic malt. Ferment with a German lager yeast. This should give you a nice Dunkel. I still have my first one lagering, but I feel that I'm pretty close to the style with this one.