ks config managers

What projects are out there for building kickstart files and maintaining
them over time?

The problem I'm looking to address involves the maintenance of a large
number of kickstart configurations over time.  What is in my head right
now is a system that has a series of configurations, each configuration
can have parts that are sort of stubs or templates that may be shared
between multiple configurations.  Updating one of the stubs causes an
update in all relevant configurations.

Many thanks,
Chris