If I were doing it, I'd forget lvm on the new drive and just make the md devices, mkfs them, mount them somewhere temporarily, copy stuff over with 'cp -a', 'tar | tar', 'dump | restor', 'rsync -av', etc., edit fstab to mount the new md devices for / and /boot, fix grub and swap the drives. If you have to worry about growing files, do an rsync once live, then go to single user mode and repeat (the second run will fix anything that changed and will go pretty quickly).
I'm sold, it really doesn't need lvm. I presume after editing fstab the nonexistent lvm config can be ignored? Never done that...
Thanks! jlc