Thanks. That's a good answer. I don't think anything like this was cost effective in the early 2000's.

A quick google turned up this: http://search.digikey.com/us/en/products/MRF24J40MA-I%2FRM/M...

A module from Microchip that looks relatively easy for someone who already monkeys with micros to add low speed wireless to a project for about $8/unit. Very Nice.

I am inspired.