Have you seen this, @Mark_Kriegsman ?! I need to see this running FastLED! This is a strange, wonderful way to bring FastLED support to the Teensy 3.6. 
For those of you that may not be aware, a while back Mark got FastLED running on an Apple //e: https://blog.kriegsman.org/2015/02/16/fastled-for-the-apple-ii/
http://hackaday.com/2017/02/21/a-full-speed-portable-apple-e/