After the whole unravelling stitches fiasco, things with Singe are going much better. This is due in large part to the giant cage that I bought to contain her. I bought the biggest dog kennel/crate/whatchamacallit that I could find, got a nice flat cushion for her so she won't get stuck on it like she was her beds with their tricky side walls, and add a regular litter box into the mix and presto, perfect kitty prison. I had to get her a normal litter box because the LitterMaid that I have now turned out to be a trap for cats with cones on their heads. That was not a fun day.
So now, aside from her howling and scrabbling at the floor trying to dig her way out, both of which actions are brought to a halt be showing her a squirt bottle of water, she is really calm. Yesterday she was sleeping so deeply that she didn't even move when I opened the door to check on her water.