I'm making a diy guitar controller for guitar hero on xbox 360. As far as i could see on the web, it's not possible to build anything from stratch and just plug in the console due to MS security protocols, so DIY controllers usually have a real controller board in the middle (like this arcade controller http://hacknmod.com/hack/diy-arcade-controller-for-xbox-360/). But some GH editions aren't playable with regular controllers, they require specificaly a guitar controller, so if I just make my custom guitar interface with a regular controller, it won't work.
Is there actually a way to interface the console without using a real controller? Or maybe sit between the actual controller and console and modify the communication to make the console think there's a guitar plugged in? In this case, would an Arduino be capable of do the job?