The ones that I have seen were done just like an 'inside' kitchen. The architects provided the requirements, or the EC just 'followed the code'.
FYI, none were 'only 3' wide'. Most are outrageous IMHO, and keep in mind NJs climate.
As to NEC requirements, by the definition, "area" could be interior or exterior. Eliminate the sink, and it's mot a 'kitchen', even thou a micro, grill, fridge, wine cooler, keg-a-lator, etc. are all there.