Actually I found it the first day the xbox originals came out. Its stored in a odd file format and is split into 800 megs a piece. Its like a part rar. If your expecting to mod it then forget it, it isn't happening.
Go into your profile using XPORT then search for a folder named halo write down the number then find the folder under 0000000000000 inside that folder you will find your halo pieces.