Yay! I've doubled my bunnies living space...
I was able to assemble them each a playpen from coated steel grids. To protect the floor/save on cleaning, I made "platforms" from thin sheets of some lightweight wood product that I had leftover from a project from years ago. I covered the wood with leftover linoleum tiles from when I'd covered the kitchen floor. I connect the playpens to their cages with extra double-ended snaps hanging around my barn.
Their cages open directly into the playpens (I was able to undo the sideways-opening door and re-attach it so that now they are both ramps). They've pretty much taken over the little room they're in, although I can still step around them and just open the door into the room). but the pens are lightweight and easy to maneuver, so I can stack them in a corner at night when I tuck the bunnies in.
The grids were on sale and half the price of other sets, so I got 2 boxes of them and still have 15 left over. In the spring, I'll be able to move them outside and increase the size of the pens to give them more space, grass and sunshine
Here are the grids:
!
I also ordered steel cage connectors for more permanent and safer connection. I'll re-do in the spring with the steel connectors. The plastic are fine for indoors and for now!