We have added sender/receiver interfaces to components. So far, we only had client/server interfaces, which define a set of operations (with contracts) that can be called by clients. Sender/Receiver interfaces are different in that they simply define data items that are exchanged by components. While this sounds like global variables, it is not: the component instances and their sender/receiver ports still have to be wired up. Also, this kind of interface makes most sense for a system that employs some kind of middleware (although you can of course use them in a non-middleware setting).
In fact, we have built these sender/receiver interfaces in anticipation of the BMW Car IT case study that has started recently, where we will soon be building an integration of the AUTOSAR RTE with the mbeddr components language.