[Zope] Cost estimation for developing a Framework or CMS

Good evening! This has nothing to do with Zope directly, but I'm in the hope one of you might know a source for an estimation of the costs (some kind of study or report; manhours/days/months as unit would be fine) for implementing a Web Application Framework (like Zope, or something of a smaller scale) or a CMS. Are there some figures of this kind available for Zope, too? I need this for stuffing my thesis a bit with numbers... Thanks! Martin