Actually it has been. You had the ability to link up your Gizmo account which was a 100% pure VOIP service. Then, from Gizmo you could link in an Asterisk serve

Actually it has been. You had the ability to link up your Gizmo account which was a 100% pure VOIP service. Then, from Gizmo you could link in an Asterisk server with SIP. Google then bought Gizmo and put it on ice. You can use freeswitch/asterisk to login to your Google Talk account and take calls from your Voice account now and do the same thing.