> Get an iPhone subsidized, pick up this cheap Android device, and suddenly be able to develop on both platforms while paying <$65 a month for data
Why not get an Android on the same carrier as your existing phone? If it's for dev use then it doesn't need its own plan; just swap your existing SIM into it. Not like you're going to be developing for both phones at the same time.
This is what I did; I have an N1 and an iPhone 4, and every now and then I swap my SIM into the N1. Just needed to get a MicroSIM adapter off Amazon and everything works great.
Why not get an Android on the same carrier as your existing phone? If it's for dev use then it doesn't need its own plan; just swap your existing SIM into it. Not like you're going to be developing for both phones at the same time.