Thank you everyone for your input. I have followed up on the suggestions and come up with a design. I like certain aspects of the chicken tractor idea, but some other aspects I don't. My plan is a chicken tractor (ish) coop combined with free ranging.
Things I like about chicken tractor:
1. no floor, no bottom to clean out.
2. continuous/daily movement to cover property with natural fertilizer and pest control
Things I don't:
1. cheap construction; Most chicken tractors look shoddy (this is really my wife's thing. She's the one with standards and wants it to be aesthetically pleasing) and structurally weak.
2. light weight, would blow away in my area (Texas gulf coast, hurricane country)
3. chickens seem cramped in there; would like to see them roaming around, being chickens
4. takes an adult to move it
5. The bottom part is almost always wood, which rots in contact with earth.
So here's what I've come up with; please provide constructive criticism. If any changes are needed then I would rather do them now, before I get too far along.

(roof ridge cap not shown, nor wheels)
It's a simple structure designed mostly around the dimensions of the scrap R-Panel I have on hand. some details:
1. It has no floor
2. The narrower end walls are hinged. With both doors open, it would be like an open corridor. One door will be open for the birds to come in/out. The other end will be the back side of the nesting boxes, so it can be opened to easily retrieve the eggs.
3. It is a wooden structure constructed of treated 2x4s skinned in R-panel, but sits on a metal frame which will contact the ground. In my experience metal takes a lot longer to decompose in contact with earth.
4. It has wheels centered on the coop, which are mounted on offset arms. The wheels can be easily rotated up, so that the coops sits on the ground, or down, lifting the coop up, to be moved.
5. It is longer and wider than it is tall, and is stout, relatively heavy, presents a low center of gravity and low wind profile, to keep it from blowing away. Despite being heavy, the wheel lift arms have a very high leverage factor and with the weight centered on the wheels it should be easy for my 7y/o daughter to lift it and move it to a new location (this will be her chore).
I have purchased 500ft of welded wire fence and 70 t-posts from which to construct temporary/semi-permanent paddocks. The plan is to cordon off about 1/4 acre of property at a time and move the coop around inside there daily. I have 5 birds currently and I plan to get 5 more. If I can leave them in the same 1/4 acre all year without them depleting it, then I will shift the paddock around each year, planting my garden (about the same 1/4 acre) in the place they were the year before.
