Great website with a bunch of do-it-yourself rabbit enclosures for house rabbits!
Another awesome rabbit cage. Storage cubes, zip ties, PVC pipes to stabilize the shelves. 1"x3" boards to help stabilize the height of the cage. The shelves are plywood that have been varnished to death (so no accidents get absorbed), covered in towels secured with binder clips.
Expedit shelf from ikea to rabbit hutch, yep I am doing this