SlideAware has created a slick web-based solution for managing the life cycle of Powerpoint presentations. They started using Python, then they switched to Rails, and finally settled on pure Erlang. Using Erlang, they replaced a combination of Lighttpd + RoR + SQLlite + XMLRpc + Jython + Lucene with the much simpler and highly scalable stack of Yaws + Mnesia + Erlang.
They wrote an interesting article describing their technology choices. Check it out at http://slideaware.typepad.com/slideaware/2007/04/from_python_to_.html.