I got my Gazelle from Calhoun Cycle. Gazelle - Calhoun Cycle. Ther are a few other dealers ans previously mentioned, just takes some searching.
You can make something similar, I did using a Robin Hood sport. You will end up with a very practical utility bike, but it wont have the same ride quality or bullet proof durability. I've put over 2000 miles on my Gazelle so far, it hasn't needed any maintenance or repairs yet, and I ride it daily in a wet climate on poor roads including gravel.

There's also a dealer in San Francisco, http://www.mydutchbike.com/