But I threw in the towel and got a pair of JeeNodes from Modern Devices. They are RFM12-B based and and I'm quite pleased. They are Arduino compatible and have decent library support written by the creator. You can set a radio id and group id so you can have more than a pair going. They are transceivers too so you can do bidirectional. The Arduino library comes with tons of examples. I wished the getting started documentation was a little simpler (I am writing one as a blog post soon) but it's entirely possible to figure it out in a few hours.