[Zope] References and Consulting

Hi there! I have a question ;-) We're thinking of using Zope for a rather big project and because of that I wanted to ask if there are some references where Zope is used in a bigger environment. Also I would be interested in which companies in Germany are doing consulting for Zope and the like. We need this to have some arguments against other technologies. Are there maybe any benchmarks between Zope and Websphere or similar servers? Thanks for your answers! :) -- christian