i am going to give you a few of the simple steps i took to customize my 360 and for very little $$$
Step 1: Taking apart your 360
you can find out how to do this through many sites. NOTE: this will void your warranty
Step 2: Layout your design
i chose to do a simple design i found on this site. you can draw out any design you like, just be careful and do whatever your artistic ability will allow you to do.
i was playing around with my other xbox so i thought id also show you this design too. it may not stay this way i think i am going to make the corners bigger and maybe a little fatter lines.
Step 3: Cutting out your design
i used a dremmel cutting about 1/4 to an 1/8 of an inch from my line and sanded to my line. i would suggest practicing on something else first (only pic i have related)
Step 4: Taking disc drive apart
i do not have any step by step for this, if you have problems check online to find out about taking apart. you will find i believe 4 screws on the bottom very simple.
Step 5: Disc drive layout
just as the case use your imagination. just leave a piece connected (kinda obvious) so the top wheel will remain in place.
Step 6: Cutting out your design
same as the case i used a dremmel and cut about 1/8 of and inch from the line and sanded to my line. (sorry my pics are not specific i did it over a period of time)