This is true, but I am afraid it doesn't have much connection to the problem. Even if you 'rfork n' (and have a copy of the namespace) the file /dev/wdir is simply the same file in both namespaces...
Yes, I realized after I hit send that I wasn't very clear about what I was trying to say. I wasn't trying to address the wdir issue, but your allusion to the namespace behaviour not making sense. Knowing how and why namespaces work as they do is critical to understanding and using Plan 9. It's important that you read and understand the names.ps paper and then spend time experimenting with namespaces. For most people it's the hardest part of the system to wrap your brain around, but once you get it your universe gets a lot bigger very quickly.
--lyndon