The Scholars' Lab has Released BagIt and SolrSearch Plugins for Omeka.
Here's an excerpt from the BagIt announcement:
BagIt is a specification by the Library of Congress for creating containers of files with metadata. . . .
The first part of this release is the BagIt PHP library. This is a generic PHP library for working with BagIt files. . . .
The second part is the BagIt Omeka plugin. This is built upon the BagIt library and provides an easy-to-use user interface for it.
Here's an excerpt from the SolrSearch announcement:
SolrSearch allows you to replace Omeka's default search with Solr. Solr is a standard, popular, open source, fast text search engine server. It handles hit highlighting, date math, numeric aggregation functions (mean, max, etc.), indexing for 33 languages, replication, and many, many more things.