My rabbit and cat are buds. 
Well, as much buds as my evil rabbit can be with any creature. From the look on his face, I swear he plots the world’s demise.
My rabbit has the run of the house along with the cat, so they spend lots of time together and either ignore each other or one tries to be nice to the other (with the usual funny results).
However, we had the rabbit first and got the cat as a kitten. I think it would be more difficult with full grown cats and a smaller rabbit.
My rabbit is a Holland lop, so his small size hasn’t been a problem.
Lady
I thought the helpful people who responded to this thread might like an update.
Under strict supervision, we opened the door to Mr. Bunbun’s room, where we had been letting him run outside his cage. He appears to be already box trained - we haven’t found any unpleasant surprises yet anyway.
Our best hunter cat, Widget, came around the corner and looked in the room. Mr. Bunbun was very curious about Widget and went straight for her! We have laminate wood floors, kind of slippery and Mr. Bunbun’s toenails make a racket on them. Mr. Bunbun went tappity-tappity over to the cat, who jumped three feet in the air and ran for her life, scrabbling madly on the slippery floor like a cartoon cat with fifteen legs! She has kept a wary distance ever since. We think the toenails clicking on the laminate floors must sound scary to them!
We felt like Hoover, our big orange doofus of a cat, wouldn’t care one way or the other - and we were right, but he keeps his distance. We know he’s thinking “Oh, brother - what have they brought into the house this time?”
D-Day, our youngest cat, puffed up four times her normal skinny size and also ran for her life when she caught sight of the rabbit! She came back later though and ate some of the bunny’s dry food - we thought that was kind of strange, but D-Day has her strange days. We think she’ll be the brave one that actually plays with the rabbit. but right now she doesn’t altogether trust that weird-looking cat.
So we are pleased with the status. The cats are terrified of the big fierce bunny who appears to want to get to know them! So we let Mr. B run around the house (we put up all the wires and always keep an eye on him).
I would love to post a picture of this monster wabbit, but our digital camera is on the fritz.
Thank you all again for your words of wisdom and kindness and comedy.