I never noted VIMAGE, the kernel virtualization project of FreeBSD  until I read that PCBSD was making changes in order to use VIMAGE on jails.

The idea behing VIMAGE, also called VNET, is to provide a self-contained-per-jail-status in order to virtualize modules and their behavior. This translates to the opportunity to virtualize network stacks on a per-jail basis, something that reminds me the OpenSolaris CrossBow Project.