An installation of D-NET including the services required to deploy a repository aggregation infrastructure can be found here:
https://zenodo.org/record/31693#.Vg0_9pff3rF
Specifically, the installation contains the services and workflows require for:

• Collection of metadata records in oai_dc format via OAI-PMH, FTP, local file system, HTTP.
• Transformation of the collected metadata records into an internal format named DMF (Driver Metadata Format)
• Indexing of DMF records in a Solr full-text index
• OAI-PMH export of aggregated metadata records in DMF and oai_dc formats. More formats can be added at runtime by providing a dedicated XSLT from DMF to the desired target format.

If you are interested to play with the full software toolkit, understand its internals, please contact dnet-team@isti.cnr.it. D-NET is Open Access, we are open to share our codebase and contributors are more than welcome.