You might want to look at how MIMEDefang does their distribution. They have recently been breaking usable parts out into generally useful modules and putting them on CPAN.

The files I know about were released by dfs and David O'Neill. It may not be exactly how you do it, but it is a successful large scale project that had some of the same problems to solve.

dfs is very nice, he may have be able to tell you why they chose to do things a certain way if you ask.