For European fixed speed traps, you can use the free
http://www.scdb.info/en/plugin-google-earth/ database. It supports the simplidied adding process with automatic icon assignment.
For mobile radar, you have to do the icon assignment by yourself with individual asc files.
The x'tras you're talking about require not only the support of ov2 format, but also a complete knowledge of the database structure, generally packed into a zip file to extract and dispatch individual files/speed trap in the correct category.
Up to now, in addition to scbd, I've found only one non french databas of this type, an italian one (
PoiGPS - Punti di Interesse per Navigatori Satellitari). Do you have example of other database of this type?