While considering material for a filler thing suggested by Ben, I've learned something new about the PitW world.
The main reason there is no were-housecat variety is that in no biome is the housecat (or, in the wild, the Egyptian desert cat) an apex predator. Even in the desert from whence it came, it is outdone by the fox, the wolf, and the jackal.
I've had that in mind for ages, but only today did I realize that, for the very reason I just mentioned, there are- or rather WERE- werejackals.
They have been extinct for not less than twelve hundred years, possibly as many as sixteen hundred years.
There are a lot more details about them, but they will wait for use in the aforementioned filler.