Yes, well I can confirm that it is and has been working on Dwarfpool without problems and afaik Dwarfpool is the only pool that supports it. But the pool mines less and less blocks so it's starting to eat into profits.
I somehow don't understand why pool operators and miners who invest into (or provide service for) mining a cryptocurrency, that has anonymity as its founding stone and ingenious mathematical solutions to provide it, do not demand or at least have some incentive to increase the use of cloaked transactions. The fees for z-transactions are higher, but they aren't THAT high. Without them, what's the point?