I've modified a copy of minirt24.gz, and tried to start it. I changed the startup message, and that worked, so I know it loaded properly. I used the following commands in the GRUB console:

root (hd0,5)
kernel (hd0,5)/dir/to/linux24 bootfrom=/dev/hda11 desktop=icewm splash
initrd (hd0,5)/dir/to/minirt24_new.gz
boot

I saw my custom startup message, and then it shoved the basic console at me. So I tried the normal minirt24.gz, with:

root (hd0,5)
kernel (hd0,5)/dir/to/linux24 bootfrom=/dev/hda11 desktop=icewm splash
initrd (hd0,5)/dir/to/minirt24.gz
boot

And I saw the default boot message, and get the same problem! It works, however, when I boot the Knoppix CD and from the ISOLINUX prompt, type:

knoppix bootfrom=/dev/hda11 desktop=icewm splash

So I'm wondering why. It says it can't find the KNOPPIX filesystem. Help!