i doubt they will use a signed chip for the controllers, as it would piss off 3rd parties, anyways the output of the "X" on the x360 controller should allways be the same, this part seems very easy to make.
on another note, the wireless connection of the controllers was allready discussed by MS, there is a connect button on the x360 in order to "register" the controller to the console. The ring of light on the console is seperated into 4 led sections, or quadrents, each quadrent representing the controller which is in use, upper left is 1st to lower right which is 4th (may be different in right to left countries), the ring of light led corresponds with the led on the controller.