It would be nice to have a GV to sip conversion box. Obviously needs to be compatible with the new WEBRTC standards. WEBRTC compatibility also might mean it could be updated to work with new services, maybe non-Google, that have not been introduced yet. Doesn't need any FX ports, just Ethernet. At least 7 SPx's with one SIP compliant that would work as a two way gateway to another OBi or pbx or IP phone and would not need OBi-talk to function. A mini-VPN to tunnel in a softphone from a mobile location would be extra sweet.
WebRTC to SIP protocol converter projects are in the works. I am aware of a Raspberry Pi based solution in development. The Raspberry Pi device will act as a SIP proxy for the WebRTC service. Look for new solutions to appear after the new GV protocols have stabilized. Google is your friend!