This looks quite similar to what the OP wants. Although I'm not sure of the licensing issues.
Thor Lancelot Simon <tls%panix.com@localhost> wrote:
> One key idea that may help you is not mine -- it's due to Matt Thomas. It is
> the idea of, making an *additional* bunch of sets files specifying
> exactly and only the parts of the system you need. Then install those
> (embedbase.txt, embedetc.tgz, etc.) rather than base, etc, and so forth.
> That will give you a simple, maintainable way to build a NetBSD that
> does what you need, is still a coherent whole rather than a pile of
> disjoint "system packages", and is much smaller.
One interesting feature is also to crunchgen(1) binaries to reduce
memory footprint, which is interesting when booting a kernel with
ramdisk. It works nicely, but is not documented very much.