How to build a custom kernel

or "Where is linux-lts-backport-natty-source-2.6.38?".

We'd like to compile a custom kernel based on the natty backport-kernel for lucid. We need this for our live-cd project (http://privacy-cd.org). We are currently using the stock lucid kernel as base and build our kernel from the corresponding linux-source-2.6.32 package by adapting the config and using make-kpkg to build the kernel.

However, there is no such linux-source package for the natty backport kernel. Why?

Is there any other way to compile a custom kernel. The source package of linux-lts-backport-natty is huge and seems to build all kinds of flavors and architectures, along with a bunch of separate module packages. We don't need this, we only need the generic flavor for i386.