I’m jealous. That is the way I would have preferred to do it if I had an existing light switch to replace. 
I ended up using the Virtual Thermostat smart app but it isn’t the ideal control of the speed control of the fan. It basically triggers it to whatever setting it last was set at. It would be better to have it trigger it in stages like low, medium, high speeds if the temp in the room continues to rise. If I want to dive into groovy someday I’ll attempt to tackle it. The device type for the GE is a **Dimmer Switch and Aeon is a Aeon Illuminator Module. But something is amiss because SmartThings crashes sometimes? Still trying to figure it out.
**UPDATE: I switched to @ChadCK device handler It is MUCH better than the standard dimmer one I had been using. And I use my custom 3 Speed Ceiling Fan Thermostat for control.