Since you plan to open your design, why did you go with teensy which is not open source?
zapta, few reasons.... I wanted a more powerful microcontroller than an arduino and I'm no expert in electronics... most arduino compatible hardware only go till 48mhz... I'm running teensy overclocked to 160mhz and the lcd refresh rate is still not what i wanted...
Above all, I understand Paul idea of not opensoursing the bootloader of teensy... still he makes a huge effort for the "arduino" community with libraries and improvements... also keep in mind that this is not supposed to be a product, it s project that I made for fun, and sharing the code / designs it is only intended if people want to reproduce the project.
Another point is that, if you want to reproduce, but don't want the buy a teensy, you can always get the compiled code (hex file) from the teensyduino and buid yourself a MK20DX256 based board and use the same code, the only difference is that your board would not have the bootloader, that is not necessary to run the code.
I see a lot of people criticizing Paul for his decision of not open sourcing the bootloader but I see very few people trying to create a bootloader for those chips from scratch.
If you have another option of development board, that a hobbyist could get his hands on, that matches my requirements (at least 120MHZ, arduino compatible) and 100% open source i would love to try.