I added the CC3000 breakout board to my breadboard and ran the examples that come with the adafruit library. I powered it from 3.3V first and wondered why it didn't initialize, but it did after I gave it 5V. It's getting a bit crowded:

The input device's screw terminals moved to the right, where the GPS is. The CC3000 board is between the display and the Teensy because I wanted to have the SPI devices close to the controller.

I'll now have to figure out how to mix all those different SPI drivers for the Display (my own DMA SPI driver), the SD card (SdFat) and WiFi (CC3000 driver). I expect that to be quite painful.