I am not sure about using Python scripts for Indexing etc...
However, most of the enterprise level CMS do provide an advanced "Search Engine" or integrate with few of them.
Alfresco is bundled with "Lucene", an open source and Java based search engine. Lucene is very flexible and powerful. You can index and search millions of documents, web pages and various content (such as Images, Videos, PDF etc).
Alfresco provides a powerful concept called "Aspects" (dynamic properties) to extend the content model and to enable indexing and search.
You can find more information about search in our book (http://www.packtpub.com/alfresco-3-enterprise-content-management-implementation/book/mid/160609knbhtv
) as well as in Alfresco's Wiki Pages (http://wiki.alfresco.com