I'm selling a Toshiba SD-R6112 laptop SuperDrive that came out of a PC. I believe according to this link it will work in the later generation white iBook's. Doing a search in the drive database, I came up with a few instances of people using the SD-R6112 in there iBook's and Pismo's. Please note that this drive comes bare and you will have to supply your own bezel.
Price: $150 + shipping.
Here are the specifications:
Write:
2x DVD-R
1x DVD-RW
16x CD-R
10x CD-RW
Read:
8x DVD
24x CD