Max number of USB controllers for pc version

Has anyone tried to connect more than 3 controllers to their pc? In 2k12, 4 was impossible because it only allowed for 3 game pads + 1 slot force/assigned to the keyboard. Ridiculous. My friends and I used to play 2v2 all the time in previous versions and even 3v2 in some NBA Lives. Now, one of us is stuck using the keyboard.

If someone can somehow mod this feature, it would be awesome. I remember someone modded MADDEN to allow unlimited controlled teammates rather than just 1 guy controlling one team vs another.

if i plug a second controller into a diff USB slot it says its player 6. so idk