Hi Andy, If you cannot get hold of a Tenba what about a Nikon Lens Case CL-L2 and cutting off the Nikon badge, I went through looking for a bag for my d2x and 500 f/4, I got a lowepro aw600, it was massive to big for me, I then purchased the CL-L2, I am fairly sure you can get the lens fitted to the body in the bag?
If you want you can try it? I was intending to keep the bag for when I purchase a 300mm f/2.8IS but if you want to buy no problem.
http://www.europe-nikon.com/product/...cessories.html
Cheers