It's entirely supported, you just need to make sure that if you make /var a separate partition, you make /var/run and /var/lock under it as you note here.
This is documented in several places -- The initscript mountvirtfs fails to mount /var/run and /var/lock if /var is a seperate partition https://launchpad.net/bugs/63986 -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
