Yes. I built something on top of OpenVBX a while back: https://github.com/andreioprisan/igroups
I wish there was a universal web-based VBX that would work with a number of providers, either self-hosted or hosted by the platform provider themselves.
Our system is designed to run on any of the modern cloud telephony APIs: Twilio, Plivo, TelAPI, even your own RestComm stack. I don't know of anything OS though.
Can you elaborate? Are you talking about your own startup product?
I started working on a nodejs-based such platform a while ago for fonefy.com but never quite had time to finish it
Interesting. Do you want to drop us a note at hello@plivo.com and we discuss more about this.