onederer...
I don't know if this will help or confuse, but I modeled my system from this. Simply put, he is installing boot loader for each OS on it's own partition. He has grub installed on a partition of it's own with no OS. He activates grub to boot and chainloads to the other bootloaders to boot that OS. Very clean, very clever and very repairable if needed. You can setup the grub menu to load partitions that don't even have as OS installed yet! It will just error out and bounce you back to the menu for a different choice.
This post is a little dated... I believe the newer SATA drives will only allow 15 partitions...

Here is the layout of one of my systems:
(hd0) 698.64gb (Seagate 750gb)
hda1 C: 200.2gb Windows XP SP2 (fat32)
hda2 D: 200.2gb (ntfs)
hda3 GRUB 23.53mb (fat16)
hda4 298.22gb extended
hda5 1.99gb linux-swap
hda6 200.2gb Sabayon (ext3)
hda7 24.01gb (empty) linux (ext3)
hda8 24.01gb (empty) linux (ext3)
hda9 24.01gb (empty) linux (ext3)
hda10 24.01gb (empty) linux (ext3)
(hd1) 372.62gb (Seagate 400gb)
hdb1 E: 186.31gb Windows 7 Ultimate (ntfs)
hdb2 F: 186.30gb (ntfs)
The link:
http://www.justlinux.com/forum/showthread.php?p=861282Penny