Wow, this thread has been entertaining!
I had an Owens Hunter series two hole box that I bought at Cabelas. It didn't have any storage on the top or the bottom and the only insulation it had was blue corrugated plastic cardboard.
I liked the box because it was light enough for me to move by myself but it had it's problems as well.
I put a digital remote thermometer in box so I could keep track of the temps in the summer and winter. That box was cold!. I put prairie hay down in the box and left my GSP in it one night when we couldn't take her into the motel. When it was closed up tight it only got up to 32* F in that box. It was cold, -5*F but I felt bad about her having to be outside in that cold of weather. I ended up sneaking her into the motel, got caught and evicted in the middle of the night but that's another story.
I traded that box off and bought a Deer Creek Houndsman series box. It's well built and well insulated, keeps the dogs warm in the winter, cool in the summer and has top storage. I couldn't be happier with it except that's it really heavy. It's a two man job to move it from one truck to another or take it out for storage.
I'd like to have a box that I could move by myself but I don't know if that is an option to keep three dogs warm and protected.