This should probably be the default since 2.6 headers/kernel is now the default, if I'm not mistaken... The current /etc/hotplug/scsi.agent still uses the old form: 5) TYPE=cdrom ; for CD-ROM, while scsi.h in 2.6 uses TYPE=rom instead. There could be a simple patch for 2.4 headers...
sys-apps/hotplug is useless with any recent udev version, and 2.4 kernels are no longer supported. Unmerge it and move on. WONTFIX.