Genkernel

genkernel is used to automate the build process of the kernel and initramfs. Some of the general features:
 * configure the kernel sources
 * build bzImage and copy to /boot
 * create initramfs and copy to /boot
 * create symlinks in /boot
 * add custom content to initramfs for encryption, splash images, extra modules etc.
 * compress initramfs
 * configure the bootloader

Installation
You can install with the following command:

Configuration
The configuration file is and is very well documented.