[tobeychris]

For building your own ROM at the very basic level, try the sticky'd tutorial

As for getting your own SYS/XIP.... I'd stick to playing with packages, rgus, provxmls, and other easier things until you have a better understanding, then look for SYS porting guides... if you get to that point, you've p***** most of the poeple here. If you really want, you can then try XIP porting, but that requires a lot more computer knowledge.