It's something that is asked now and again, but, no, I am not aware of any concrete plans to integrate them.
It would be helpful to identify what is actually being asked for as, presently, the only REST API out of Accumulo is the Accumulo monitor which provides inside into a cluster. This is no client API over REST which is what Knox would traditionally be integrating with.
Understanding what kind of integration you're asking for would be helpful. Thanks!