I've not read this entire thread so far, but did want to chime in:
When I was young and able to kneel etc. I built my own coop and yard. That was almost 30 years ago!
I want to get back into bantams but was trying to figure out what I could get without breaking my bank account, and without resorting to the cheap stuff I've seen at Tractor Supply.
I'm about ready to seriously find a coop, so I went online and started searching. Everything is the same, cute "Amish" designs, cheap, cheap, cheap...or out of my price range.
About ten pages into the search I found a company in Texas that I think I will do business with. The coops have lots of ventilation and their designs include what I was looking for, something WITHOUT a solid bottom, sides with hardware cloth instead of chicken wire, AND cedar shingles! I want to move it around, too, and some of these have wheelbarrow handles and skids. They also have interesting designs for a portable fence.
For your perusal and input:
http://www.ranch-coop.com/large-chicken-coop-B.html
http://www.ranch-coop.com/A-shippable-4x4.html