Is there a lib with full nkro support for 105 key keyboard?
It depends on the type of keyboard you are talking about.
For a matrix style keyboard you can read about it here: http://playground.arduino.cc/Code/Keypad. The default settings support up to 160 keys with 10 key rollover. However if you want to eliminate key ghosting and key jamming you will need to have isolation diodes installed on each key.
For using a regular keyboard with the Due or Leonardo http://arduino.cc/en/Reference/MouseKeyboard it looks like you can get nkro support by using the function calls Keyboard.press() and Keyboard.release(). You will still need a library for reading the keypresses of a PS2 or USB keyboard.
Check here http://playground.arduino.cc//Main/InterfacingWithHardware#keyb for a list of keyboard libraries on the Arduino playground.