You touched on some very good points (estel).

The vpn/encryption is merely redundancy, and an extra blanket in the event vpns aren't as (relatively) secure as we think. Back doors, weak passcodes/encryption methods, etc, etc.

And yes, over a vpn link i guess you wouldn't need a voip gateway, since they are on the same "virtual" lan in a sense.

I think it would be fantastic if someone devised a small pass through box, along with the hardware/software to go along with it, that encrypted/decrypted your average ptsn phone data end to end. Something cheap, easy to use, and simple for the masses. Like the digital converter box from the analog tv switchover a few years back.

Obviously without the federal backing, but with all this nsa data mining stuff in the news, you might just get enough public support to bi&#h-slap the intelligence agencies and see how they react.

If you wanted to cut out the simple/easy, i bet you could whip something up with an arduino relatively cheaply that would do that too.

More of an activism/symbolic thing that the people are not ok with dragnets and databases of all our personal data. Be it phone metadata, content, or the fiber-splitters on the IP backbone lines att (and almost certainly the rest of the us telecos) have let the nsa operate since 2006.