In case anyone is interested here is a post on how to communicate with SmartThings using a Propeller. The propeller driver is this post uses standard ZigBee Home Automation device types and clusters to communicate with the SmartThings ZigBee radio. It can be the foundation any type of build your own hardware and is based on ZigBee Home Automation standards.
Sorry about the ugly URL
Parallax’s Propeller is an 8 Core 32-bit RISC based processor with 32 I/O lines. I have created several commercial devices with it over the years and recently just released my communications library to the propeller community in the above URL.