Looks interesting - I wonder how the window opens if there is sturdy mesh in place. It looked huge in the pic but was 4x4, I think.
We need to replace the shed before the Winter and are just holding off while working out what we need to bear in mind. I've already decided we need the windows in a different position and that a stable door could be useful too. Perhaps we could design it so there is a run attached and in the shade? And am keeping an eye on the temp in the shed with a max-min thermometer as the weather warms up for the Summer. We might move the large hutch outdoors but then I think we might have to sort out a waterproof cover.
I am concerned abot whether mice will move in, though, especially after reading the sad postings recently.