Tom Keating drew my attention to Konnect, a new Peer 2 Peer telephony system. Years back one of my first VoIP clients inside my agency was a company called Popular Telephony. The company fell on hard times and the intellectual property was eventually sold off for very little money. The idea was simple. A P2P solution for business. The way it works is using the concept of distributed hash taobles.
Based on Tom's account, Konnect seems to be Peerio brought to life.