The TrustedBSD features are used by appliance vendors who base their product on FreeBSD. Applicances have very narrow profiles of acceptable use and thus it's actually sane to develop policies for them.
LOCK System http://www.cyberdefenseagency.com/publications/LOCK-An_Histo...
Sidewinder firewall http://www.ittoday.info/AIMS/DSM/83-10-35.pdf
Flask project/architecture https://www.cs.utah.edu/flux/fluke/html/flask.html
Nonetheless, the old stuff (esp LOCK & LOCK/ix) are still stronger in security architecture and design despite all these years. Good design is timeless I guess. :)
Note: Cambridge's CHERI project and CheriBSD are the cutting-edge for FreeBSD security as they do capability-security from hardware up with FreeBSD already ported. Also supports Capsicum, Flask, and separation kernels if one wanted. True integration of each major branch of INFOSEC. :)