Before Android became a success, I led the development of an operating system with a JVM-based userland for VoIP devices: http://d2tech.com/1-products/mcue.htm
It was designed to use multiple IP communications protocols and to present a unified view of contacts' presence across all the ways they could communicate.
It was designed to use multiple IP communications protocols and to present a unified view of contacts' presence across all the ways they could communicate.