I'm considering creating a custom Teensy 3.6. The notional design concept would be about a 25 x 25 mm board with high density connectors exposing all of the I/O (think Intel Edison, which was 25 x 30 mm and used two high density connectors). In addition to the MK66, I would likely add 2-4 SPI flash storage IC's (for data logging, the goal would be 128 - 250 MBytes of total storage), an MPU-9250 IMU, a BME-280 environmental sensor, and an ADC (at least 8 channels of >20 bit resolution data). All components would be -40 to +80 or greater temperature range. The boot loader would be available on a daughter board.

Price, unfortunately, would be around $70. The price is much higher than the Teensy 3.6, but the advantage would be a very capable microcontroller and peripherals integrated into a small package that could be integrated directly on an end product. I'm wondering if there is any market for this? It changes my design whether I would make a more general purpose Teensy 3.6 "Pro", as described, for a wider audience or a purpose built component. Any components that I'm missing that should be added? Or components present that would not be useful?