Athens-based Get has released a platform for building SDI portals under a GPL v.3 License. The platform aptly named GET SDI Portal, was developed using a pure open source technology stack (PHP, OpenLayers, ExtJS and GeoExt) and it provides search functions for Catalog Services, displaying WMS and WFS layers as well the “usual” map navigation and map management tools.
According to the company, the next version will include search function compatible with the INSPIRE EU directive (among other enhancements). You can download it from http://www.getmap.gr/v2/site/files/opensourcegis/getsdiportalv1.zip
If you want to see it in action, it has been implemented for Greece’s Regulatory Authority for Energy (RAE)