I've never seen one marketed that way, but when we had our barn cat we had a little dog house for her and we blocked off part of the door with a board so the opening was big enough for her to comfortably get in and out but too small for the dogs to get in.
Cascadia- OTTB mare. 04/04-05/10
If love could have saved you, you would have lived forever
You can buy a large dog crate and either a) cut a hole in the closed door or b) cover the entrance with wire mesh or a board and cut a hole in that. I'm pretty sure you can buy or easily make crate covers
If possible, a) is best because you can just open the full door to clean or feed.
Ayup, I like BGH's idea. Just buy a regular wire dog crate a cut a hole in the door. Similarly, I cut some kitty-sized holes in a 4' baby gate to allow for EASY old kitty ingress and egress while keeping the dogs out of the room.
Fancy, fancy. I was thinking a plastic vari-kennel since you asked about warmth. If the cats will not be confined for long periods, I would lean towards something smaller than the enclosures you posted so it retains their body heat in winter.
Keep the wire door shut -no Aussies- and cut a kitty-sized hole in the plastic wall. But that's keeping it really simple.
You could make a nice square cat box with plywood, then line it with styrofoam, then mount the whole thing on a pole and provid or provide a small ramp. I don't see cats how cats would find a wire cage comfortingly safe when the Aussies can still see them, pant at them and generally harass them. Cats like to be high, and invisible but like to look down on things. I'd add a few archery holes (long slits) so they can see through and down on the inferior dogs and be smug.
Oh and make a second door (maybe a hole in the roof) so they have another exit.
Check out Craigslist for playhouses. Some of the Little Tyke and Step 2 models
can be completely closed with their shutters, etc. They usually run used about
$100 to $125. A friend uses a log cabin style one for her "woods" kitties.
Those links 7HL posted had some really cool ones....didn't know anyone made
any like that.