Not by default but as penguinbait said you can copy included bootmenu.conf.example to bootmenu.conf and add what you want.

It is probably a good idea to add n770 and N800 specific examples and external slot configuration to N800 example. I'll do it.

I'm not sure how it is with free space in initfs partition on N800 but you may probably edit/create the /mnt/initfs/bootmenu.conf later without reflashing initfs. It is a bit problematic (at least on N770) due to low free space in intfs and journaling nature of jffs2 system. You may edit it few times in place but then you run out of space in initfs and no further writes are possible so it is better to minimize number of writes to files inside /mnt/initfs. When you run out of space, initfs reflash and reboot is needed to have another round of limited writes. It is caused by jffs2 garbage collector that needs lot of free space to reclaim unused space and initfs partition is too small and too full for it to work correctly.