Portable OS
It'd be interesting to make a full portable OS setup. This could support booting a disk or CD image through qemu or syslinux. For a typical USB stick or hard disk, this can be done via syslinux on the MBR or such; for an iPod, you simply have to remember to hit the second partition with your bootloader.
Consider first that the iPod has two partitions, both flagged as bootable. The first partition will be ignored because it's not bootable on PC; the second, however, will be booted. For this, we can syslinux the second partition rather than the MBR on the iPod.