This is a quote from presstab in the slack:
presstab
@dromund we are working on implementing zerocoin into Pivx. We are beginning the testing phase right now and things are looking good.
Just to clarify this a bit. We are testing the primitive stages of it right now (for example I successfully created a zerocoinmint transaction two nights ago, just creation.. not broadcasted or used or anything). We have most of the implementation code in place, but there is still plenty of code that needs to be added. We are not in a testnet phase yet, but are able to start testing zerocoin mints and spends. The goal is to make a pretty good unit test suite that will give us a good idea that everything is working as it should be, then do a testnet round. Then after testnet, expand the current implementation to be very very efficient, then test. Then add an intuitive user interface.
There is still plenty to accomplish, but the summary of the current statis of zerocoin implementation is "full speed ahead"!
It is nice to see another 'AltCoin' moving the development of blockchain technology forward.
There is a lot of copy and clones out there, but there is also a handful of developers that are moving the technology forward and hopefully in a more user friendly direction. It is not all about the newest feature, we need to make this technology usable to the general public eventually.