"But, what sort of idiot client buys their phones from Cisco, a computer company"

The same person that will set in front of a game console for hours on end, that's who. They have grown up and now are our clients. XBOX phone systems are here and our client are familiar with the interface and the names. They have no problem with paying for "licensing" for a feature and never owning anything, it's the world they grew up in.

It's either learn IP or die. Toss your tools away and just plug into the existing network and go for it.