Hmm. Good question. I checked with my botanist friend at work, and the best he could come up with is that it's probably endemic to the area. Other than that, both he and I are in the dark. It's interesting though, isn't it? The leaf itself is contoured in such a way to maximise water collection - or that's what it looks like.
Second prize is some more pictures of plants from the Cradle Mountain area:
