Couldn't it just check for the presence of the lvm tools before putting them on the initrd? Presumably no one's going to have LVM without having the tools installed.
Fine with me -- Jeremy did this though so I'll leave it to him to undo it.
Except that if you don't have the requires, then you don't necessarily have the LVM tools installed when the kernel is installed. Thus, you have root on lvm, no lvm tools yet, initrd created by kernel install doesn't have lvm in it. Oops :(