From the FAQ hostplant list:

Great Southern White
- Mustard family, brassicaceae
- Nasturtium family, tropaeolaceae
- Saltwort family, bataceae

...so at one time someone on the Forum had luck with those.

I have a mustard that comes up from seed from my bird feeders...not sure what it is but the cats love it!
As far as cleome, I've never had a cat on mine! What kind do you have...do you have any clammyweed(Polanisia dodecandra)? It's a native that is also a host plant. If not, I have seeds if you want some!

We've been using violet queen cleome, which can be cut back often to feed them, and have some young giant queen cleome which can only be cut back once or twice before dying.

Bought some organic cabbage today and the cats show no interest so far :( It's hard to change their diet once they decide they like something though... we'll try with the next batch of GSW eggs.

I've seen brassicas listed here and other places, but I've never heard of a specific user/gardener having actually SEEN GSW cats eating brassica, nor have I seen any images of them on brassicas. I'll let you know how this works!