Custom minimalist build

["Matthew J. Harmon" <mjh@itys.net>]

I'm building a series of Xen (xensource.com) virtualized servers to 
compartmentalize applications such as Apache, PostgreSQL, etc. and I would 
like to provide each a custom build with only the necessary libraries.

So far I haven't found a way to do this easilly, I'd like to be as 
minimalist as possible with Debian (Xen's primary distribution is Debian), 
any recommendations?

Thanks.

-Matthew