I read at the OpenBSD Journal of a privilege separation version of Tcpdump being committed to OpenBSD current. You can see the changes in the OpenBSD source tree. (Browsing CVS source trees, as can also be done with FreeBSD, feature alone makes the BSD's coherent, understandable operating systems.
Tcpdump also has a browsable CVS Web interface.
Privilege separation is a topic I first learned about through Niels Provos' OpenSSH modifications. There appears to be interest in having Tcpdump run with less privileges. I found this thread on Tcpdump-workers take a different approach.