Oh, hey, didn't even remember I went through that very masochistic experience myself before ;p (re: the patch).
As for the initramfs stuff:
Yeah, you need to build the full kernel because of CONFIG_MODVERSION or something or other (can't remember, wrote it down somewhere in x-compile, though ;p).
You can safely disable the initramfs altogether for that very purpose in your kernel config (you won't be able to boot said kernel, obviously, but we don't care when the goal is building modules, not flashing kernels

).