Pocketwizard posted an update on their Nikon version of FlexTT5. The good news is that prototypes are already being tested. The release date is still unknown:
"So the big question is when? It all depends. There will be surprises along the way. As we learned with the Canon system, it is IMPOSSIBLE to peg a date. If things go well, it will be sooner. If there are major surprises, it will be later."