Comcast is testing a new combined cable modem and VoIP adapter in a few cities, according to Light Reading.
I'm also hearing reports that D-Link will release a line of in home networking equipment at SuperComm in a few weeks that includes a wireless adapter that has built in VoIP.
D-Link makes the voice gateway that Primus' Talkbroadband uses. I did work 3 years ago looking at the different ways to distribute connectivity throughout a house. I concluded the only way to do it was wirelessly*, but wireless was still too expensive and too slow at the time. Devices like Apple's AirportExpress show that wireless innovation is taking off again.
Hmmm...imagine a USB telephone handset plugged into the AirportExpress...
*Well, the other option was using the ubiquitous coax cabling that houses already have installed, but that required development of a IP-over-Coax. It hasn't been developed since then, so wireless it is.