Here's a community-edited page of projects using Hibernate Envers:
- TinyPM by Agilers (www.tinypm.com)
- PARP KSI POIG (a subsystem used by Polish Agency for Enterprise Development)
- SIL (a database for healthcare in Sweden)
- Partenón, an education management system in Spain, by CexC.
- VOCADO, school management system, by http://vocadosystems.com/
- scale4j - high-performance data-distributed systems platform http://code.google.com/p/scale4j/
If you are using Envers, please add your project to the list!