I have uploaded the specification of the CD-ROM Combo drive SD-R2512 here. Thanks to Ricardo Cordeiro who provided me with the pdf file. You seem to need (at least) Acrobat Reader 6 (Windows) with Japanese Fonts (will download automatically) to view it.
First BIOS update
The BIOS Update to version 0204A (original is 0203A) is available on the Asus Downloads page.
BIOS update
There is a BIOS Update for the M6800N that has a different DSDT. I have not tried it since I do not have Windows on my laptop to update the BIOS.
ACPI4ASUS updated
The CVS version of acpi4asus now supports the M6800N
Nice SuSE Linux on M6800N page
Added Link to Andre Messerschmidts Page
Kernel config uploaded
I have solved my problems with genkernel which were reported by someone else in this bugreport. I do not have the time to finish this guide, so I have uploaded my kernel config here. This config was made using a 2.6.2 vanilla kernel, patched with the latest acpi4asus patch from here and the broadcom kernel patch that is part of the linux driver packages by broadcom.
Just FYI: the ACPI problems are still not solved with the 2.6.2 kernel.