Does FreeBSD have a present/working/sane system to set per-user(or per-group) resource limits, including number of processes, file descriptors, physical RAM usage, etc, that would count all processes, and not apply to each process individually? Has anyone used it successfully?

The Linux kernel doesn't appear to have this functionality, which is...very annoying. It would be nice to find a Linux kernel patch that does this, but I can't find one that's remotely current.

FreeBSD and Linux both have this. It likely falls under the quota subsystem in both cases, although Linux might call it "process accounting".

For FreeBSD, look at the manpage for login.conf, and refer to a portion of the handbook: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/users-limiting.html . There are also some sysctl variables you can tweak.

-- jdc