Cloning OS - Kernel Won't Boot

Hi,

I have a few stand alone servers (RHEL 6.2) which I'm trying to configure OS backup procedure for.
My intention is to use a second internal device in the server with the same size to clone the boot device to it.

I created two partitions similar to the boot device - one for /boot (/dev/sda1) and another for LVM.
I added the second partition as a PV to the root Volume Group and converted each LV to be mirrored across both PVs.
I then reduced each Mirrored LV to one copy on the original PV and split the other PV to be a separated VG.
I've used dd and grub-install to use /dev/sdb1 as the boot partition.
I also edited fstab on the cloned root LV to reflect changes in the root VG name.

I then used dracut to create a new initramfs image and edited grub.conf on the cloned boot partition.

However, when I reboot the server and choose the second device as the boot device in BIOS, the grub menu appears but the Kernel does not start to load.
I get a blank screen with a "_" and nothing else, as if grub is unable to load the kernel according to what I've configured in grub.conf.

I'm certain I've missed a basic step somewhere in this procedure.
If anyone can help it would be much appreciated.
Thanks,
Yair