So as some of you might know the guy who gives Zed his voice was in a not so fine condition when the last installment was in work.
There was this talk I think it was in a Borderlands Show in which Randy told that Zed would make a return and curved a bit on the condition on said Voice actor.
As far we only have the Zed vending machines.
I am quite certain they are working at the moment to bring him back into the game and my speculation is that he will be featured in the 3th dlc.
I hope they integrate him also in the base game so he can hang out at sanctuary cause thats where he belongs to.