I'd build them myself but just don't have the time right now.
You'd be surprised what you can build over the course of a couple of days/weeks. I am constructing a quail pen similar to one at this link (
click here) with 3 removable pens, so maybe it's not "exactly", but close. I think I have 3 hours into it so far; I have 1 cage fully built, the frame of another and the shelf / frame for the system cut and ready for assembly. Each night I spend a half an hour or so on it, so I am still able to help my kids with their homework as well as helping the wifey with dishes or whatever else needs to be done around the house.
Also, for what it's worth, I have no "real" carpentry skills to speak of, and with the exception of a drill, I don't have any power tools. My hand tools work fine... I just don't like paying 80 dollars for something that I can build spending a quarter of the cost, which is what I'm seeing when I look at the photo.
My quail eggs arrive this friday and will go into the incubator saturday, so I still have time to complete my cages, and my brooder is already on stand-by.