Recently the Gentoo hardened project seems to have some serious bugs, particularly with the grsec kernel. I have been forced to switch to CentOS 6 and configure it to act similarly to Gentoo/grsec.
One of the biggest draws to grsec is the process hiding feature. CentOS 6 uses selinux and I decided to stay with it. Lucky for me, support for process hiding was added around kernel version 3.3.X
Mount /proc with the hidepid option.
I will show you the steps required to use hidepid with CentOS 6. These directions may not translate easily to other distributions of Linux.