Hello @Lucas-Figg
I am also keen on the idea of running a mysensor network without a full blown controller, so I am using an ESP8266 as a gateway to the cloud, but also as a controler, and as a sensor. It should be possible to do the same on the Spark/Particle but I suggest that you just buy a 5$ ESP8266 NodeMCU since it's ported allready as a gateway, and you can easilly add your favourite IoT cloud based platform.
For more details, look here:
http://forum.mysensors.org/topic/1973/esp8266-as-wifi-gateway-controller-node