Obihai Technology is marketing Google Voice use with their Obi VOIP-landline bridge products (SIP & OBiTALK VoIP services, $40 on Amazon).
Unfortunately there’s no way to port a landline number directly to an Obi device. Instead you have to use the T-mobile hack - port to T-Mobile then port to Google Voice (best documentation of this hack I’ve seen by the way). Once you’ve made this irksome port however, you do get to use GV’s great features from a home landline and VOIP. (Compare, however, to mix of GV, Bluetooth, Mobile, landline.)
Alas, the future of Google Voice is problematic — we know it’s going to be replaced by Hangout, but we don’t know what Google Voice features will survive.
Still, it’s amazing to watch the twisty-turny evolution of voice communication. This is NOT what we expected back in 1994; then we expected voice communication to become essentially “free” by 1998. Remember that the next time someone predicts the evolution of the marketplace based on technological innovation. The market is very good at fighting back - for example. (Use a fax machine lately?)