I don't know of any development. In any case, as far as I can see, the only languages currenlty supported by ZK are languages with a fully java-based interpreter. There isn't anything like that for perl. At the least you need some way of starting and running a perl interpreter from Java. Possible but no-one has build the bindings, as far as I know.
I suppose it's possible you can make it work with perl (by using something like Inline::Java), but I don't think it'll be as easy as the examples make it seem.