The good news is that there is a new Apache project starting incubation:
Lucene Connector Framework
This might be something useful in your case (although as of writing no code
available). You can read more info here:
http://www.lucidimagination.com/blog/2010/01/20/apache-lucene-connector-framework-
SOLR doesn't come with such things...
Look at www.liferay.com; they have plugin for SOLR (in SVN trunk) so that
all documents / assets can be automatically indexed by SOLR (and you have
full freedom with defining specific SOLR schema settings); their portlets
support WebDAV, and "Open Office" look
