Zane
I've got about 3 dozen Engenius phones setup at a resort in Boulder, same scenario as yours, but they just rent a phone to the guest as an option, so it doesn't get left in the room.
Down side is that each base station can only accept 4 analog connections, so for multiple phones with DID's to them you need multiple base stations and multiple external antenneas... it does work, but can be expensive, not as expensive as trenching and laying cable though....
D
