I'm interested in using a separate namespace for running a VPN client, so that every process I run into that namespace accesses the Internet through the VPN. That part I've managed to accomplish. 

However, some programs communicate through the loopback interface (e.g. a daemon I want to talk to the Internet using the VPN and a separate administration interface I want to access through the public IP of my machine) and they cannot see each other. 

Is there any way to configure a network namespace to use the same loopback as the global namespace?