Data Exchange Tools and Conversion Utilities (DExT),University of Essex. http://www.jisc.ac.uk/whatwedo/programmes/programme_rep_pres/source.aspx - "will develop, refine and test models for data exchange for both survey data and qualitative research data based on XML/RDF schema and will develop tools for data import and export"
Software Invariant Archiving of Relational Databases (SIARD) - Swiss Federal Archives (BAR) and Trivadis. http://arxiv.org/PS_cache/cs/pdf/0408/0408054v1.pdf - transforms relational databases into packages compliant with SQL and XML.
Xing (XML Archive Inquiry Tool) - National Library of Australia. http://www.nla.gov.au/xinq/ and http://sourceforge.net/projects/xinq/ - "generates a web-based search and browse interface for arbitrary XML content based on a configuation file which describes the structure and semantics for the content and rules for search, browse and display" (sponsored by International Internet Preservation Consortium to support deep web archiving)
Xyleme XML Server. http://www.xyleme.com/page/xml_storage/ - repository software for real-time load, storage, automatic indexing, querying and distribution of XML files
XPAT. http://www.dlxs.org/products/xpat.html - SGML/XML-aware search engine developed at the University of Michigan for diverse digital library resources