I think if you go to any reputable homebrew shop, local or online, that makes their own kits (i.e. its not a boxed up kit, they put the ingredients together themselves), you're probably going to get a good kit.
I do not have specific recommendations, as i've not brewed a dunkel kit. If you refer to a typical dunkel vs a dunkelweizen, keep in mind that a dunkel is a lager, which requires controlling fermentation temps in the 50s. I say this because I assume based on your question that you're relatively new to all this, if my assumption is off base, I apologize.
I get my stuff from either Austin Homebrew or Brewstock in new orleans, but that's just a location preference.