DH got commercial grade non slip sheet linoleum. He just got off cuts from the store, so it’s going to be a patchwork floor, but it’s super durable, easy to clean, not slick and free.
Base is a frame of 2 x 4 with joists every 13″ or so – even with the width of the cubes – running long way, then chunks running for joists running front to back. Then he screwed down a layer of exterior grade 5/8″ plywood, then glued down a second layer of the same plywood, flipped it and put short screws in from the bottom so they don’t pop through. Sam can stand on it at 230 pounds, so hopefully this can hold two should be 10-12 pound bunnies. Tonight he’s glueing down the linoleum, putting on trim around the plywood edge so they can’t chew on it as easily and attaching the hardware cloth to the bottom so they can’t get under and into everything. Casters on front and back, the four fronts and two back corners lock.