Though some significant level of isolation can be achieved today with Gresecurity's chroot restrictions and RBAC, it seems there's no simple, supported and stable way to restrict a group of chrooted processes to a sigle IP address as a source of outgoing packets. Do you plan to (ever) implement something to restrict the connect() sockets' source addresses?
There is LXC - the lightweight container implementation for Linux, similar to FreeBSD jails:
http://www.ibm.com/developerworks/linux ... ontainers/
It does restrict source addresses of outgoing connections, but I have no success to run it with Grsecurity and Gentoo's hardened sources 2.6.27-r7: patching and compiling are ok, but it panics the kernel early during boot. Any chances Grsecurity will ever work with something like that?