I am not sure why you do not use Google Voice. I have been using it for 9 years now. I have a OBi202 box attached, so I can use a normal hand set. It is our house phone.
Yeah back in the day, people had one phone in the house and everyone shared it.
But google voice I can use the box or my laptop to answer, it takes voice messages, and text messages.
All in all a GREAT service.