...or similar, at least.

I have a pendrivelinux installation on my USB stick. My laptop won't boot the USB key (FS Lifebook). I have GRUB on a CR-RW - a kind of SwissArmy boot disk if you will and I wanted to use it to boot the OS on the stick.

So from the GRUB command line from the CD boot:

root (hd1,0) # assuming sdb1
chainloader --force +1
makeactive
boot

Works a treat. Without the --force, I get a 'Boot Error'.

Pendrivelinux uses a syslinux bootloader which for some reason is not recognised by GRUB.

Hope this helps - sorry if it's not what you meant.