I'm a newbie as well and doing a lot of research, and Paula is very correct. You can conceivably convert an Airstream into a commercial kitchen, or you can convert it into a fulltime home, but you can't do both to the same one and stay legal, from what I understand. Even if this is a small cottage business that runs under the legal radar, I don't think that you're going to find even an upgraded Airstream kitchen to be adequate. The kitchens in Airstreams are more compact (obviously)--smaller cooktops, smaller sinks, smaller ovens, less counter space--and are geared to only pull so much power at a time. I'm skating at the edge of my knowledge with the electrical and gas stuff, I'll leave that for the more knowledgeable to address, but unless you lose a good bit of other stuff (like seating and storage) for counter and cook space, I think you're going to run into serious issues. I've not made candy, but I've done soap and candlemaking quite a bit, and can't imagine trying to do it in an Airstream.
Neat idea, though, and Paula has a great suggestion about the local Moose Lodge, VFW or whatever. If you can afford to have a TT for living and a TT custom-renovated as your kitchen, that would be nifty, but it sounds like a spendy proposition. If you can swing it, it sounds great. Renovating yourself seems to be something that only the truly handy and saintly patient should attempt.
You asked for links, here you go!
http://culinaryfool.spaces.live.com/Blog/cns!A7D1373D92F448FA!2769.entry
The start of 73 Overlander restoration
STEP-BY-STEP Shell-Off Floor Replacement
I always camp where I have electricity
Should I get rid of my appliances?
Microwave oven and Air conditioner
Fix up or buy new?
MoCo Loco: Airstream Mobile Office