Portland (Oregon) is a mecca for Food Carts -- many of which produce excellent foods. They tend to be grouped in "pods" and many of the pods have web sites.
There are so many that we like it's hard to list them. Once in a while my wife and I will spend a Saturday afternoon going to some of these pods and trying new things.
It's great!
Here are some articles...
http://www.foodcartsportland.com/
http://www.sunset.com/travel/top-10-...0400000039975/
http://www.portlandneighborhood.com/...ood-carts.html