Well I've been wanting to make myself a /boot partition and install GRUB on my system.
And I did all this without messing up my system.
While in slack I compiled and installed GRUB and made myself a GRUB bootdisk. I then edited my etc/fstab to add a partition that didn't exist yet and made a mount point called /boottobe
I rebooted using slack CD1 then ran cfdisk, deleted my last reiserf partition (which was empty), split it into 2. Then ran setup just to format the two new partitions, (the last partition will be mounted on /boottobe) then reboot again to slack.
In slack, I copied the contents of /boot into /boottobe/slackware. Also copied /mandrake/boot into /boottobe/mandrake. I also emptied the /boot directories of my mandrake and slack. Made
my /boottobe/grub/menu.lst and copied the stage1.5 files.
Edited my etc/fstab for slack and changed mountpoint /boottobe to /boot. Also edited /etc/fstab for mandrake and added the new /boot partition.
Reboot using GRUB floppy and installed into MBR. And after several retries (apparently I had errors when I wrote my menu.lst) I was able to boot into slack again. Mandrake and WinXP worked too.