I didn't find this too surprising, as when I first inquired a few years back about screens for my D600, I got a passive response about availability of new screens. This is of course ultimately unfortunate, as KatzEye made some great screens to allow the use of manual focus lenses on DSLRs of multiple brands. So I guess for those of us who desire and/or require proper manual focus screen, the only available resource I am aware of now is focusingscreen.com in Taiwan. I recently purchased a screen from them for my D600, and it works quite well, so I can recommend those folks.
RIP KatzEye: http://www.katzeyeoptics.com/