I've had a few different popups and hard sides over the years, and while I've liked the designs of a few of them, nothing has been perfect, the maintenance on popups is a pain, and most importantly - the wife hasn't been super happy. Every camper we've had has been "too much" for us.
My wife owns an aerial dance studio(think Cirque du Soleil type dancing), so we go to various festivals and camps throughout the year. All of them have bathrooms and most have showers, so that is not needed in our design. We have a disc-o-bed setup (seriously, check them out - coolest things ever) for the kid, and we'll be using either a full or queen futon for us. I'll be wiring up an RV style converter for 12volt and 110V plugs inside. We have a Honda 3000is generator that I'll hook directly to on the outside.
I'm still looking at the final designs, but we are going 7feet wide, and either 12 or 14 foot long. Leaning strongly towards tandem axle and V-nose. Gotta go 7wide to fit the futon and disc-o-bed sideways. There's just 3 of us now (myself, wife, 3 year old), but we want to make plans to expand to 4 soon.

I was originally planning on custom ordering a trailer with all of the 110V and 12V wiring pre-done, 2 RV windows, RV front door, barn door in the back. We are in central california, so insulation isn't as big for us as other places.
My biggest question is this: Are there any trailer manufacturing plants withing 300 miles or so of San Luis Obispo / Santa Maria California? The closest I've found has been either Oregon or Las Vegas. I'm fine doing the wiring myself (having patched up and rewired previous trailers), but I would like to have the RV doors and windows pre-installed from the factory, as well as making sure I have an interior height of 6'6" at least. If they're willing to install an RV-style converter box (12V, 110V, battery charger) that would be even better.
If there are no manufacturers nearby, does anyone have any experience with nearby dealers that were easy to work with and could customize the things I want?
Please excuse me if the manufacturer question or information is listed somewhere - I've scoured the forums for days trying to gather that information but I have not found anything.
Thanks for all of the info, and I can't wait to get started!