Quoting John Morris (jmorris@???):

> Nope, that negates one of the principle reasons to use an initramfs in
> the first place. You assume the stock kernel can see the drive where
> you intend to put this new partition; one of the big drivers of initrd
> in the first place was exotic hardware, etc. so GRUB uses BIOS
> (including extension ROMs on controller cards) to load both the kernel
> and the initrd so it can take whatever steps are needed, i.e load the
> right modules, start lvm, setup encrypted filesystem magic, etc. to make
> the main drive/partitions/etc. visible. Your idea could deal with most
> everything that didn't need a kernel module but totally fails at that
> task.

Step 1.  Compile a kernel that includes inline all key drivers including
         those needed to find the root filesystem.
Step 2.  Profit!

That's the old-school method.