programmable with the Arduino IDE? awesome! Do you have more details? is it already available?
edit, now I understand, you mean what you mentioned above...
Teensy is in development with a 180 MHz Cortex-M4F chip. A more powerful ESP chip is also coming. These 3 are probably the near-term future for people wanting more powerful Arduino-compatible boards.
I thought by Teensy you would mean a current Teensy ARM core board. https://www.pjrc.com/teensy/