Cross compiling the Android kernel is fairly straightforward. Download the whole Android source tree, source build/envsetup.sh, lunch the target you want, export ARCH=arm, SUBARCH=arm, CROSS_COMPILE=arm-eabi- and then build away in the kernel repository. Honestly, the easiest cross-compiling I've had to do this side of Go.
Sure, but most things are easy because someone else has done the heavy lifting. I was just pointing out how easy building the Android kernel is, something he described as "physically painful".