This might be the stupidest idea ever and it might already have been tried. But here's the idea;

Wouldn't it be possible to build a secondary "DOF-machine" and mount it on the viewfinder/LCD to get another 180 degree rotation? Then the image would be right again (except for the battery indicator and TC). It's 5.34 AM right now so it might not be the brightest idea when I wake up tomorrow, but I think it might be worth sharing my thoughts. :)

Cheers and goodnight
Carl

.. the rotation is not from the "DOF machine" its from the lens.. i cant see this working out for you. what cam do you shoot with?

I was thinking about putting a lens in front of the viewfinder, and then some kind of groundglass behind that.

i think your best bet owuld be playing around with mirrors... just seems that lenses and ground glass would be a complicated solution to an easy problem.