I'm convinced that lightsabres are based on force field technology, with the energy being contained in a field in a similar way that blaster bolts are deflected by shields. If that piece of metal had the effect of bending the field's course (mass spectrometer, cathode ray tube style), it could account for a scimiter shaped blade which fans out slightly. Still think it will look ridiculous though.
Well, I can't prove anything of course, but we have some good indicators- and this is from sceptical old me...
The guy is holding a red sabre and is wearing black. Two good indicators that he is a big bad guy. And it LOOKED like they were posing before or during a fight.
Now, it is highly likely that Christopher Lee is playing a bad guy, for a lot of reasons. COULD be an enormous bluff, of course...
And if he is a bad guy, it is likely he is the new bad guy sabre opponent as well- it is very difficult to see what else he could be- presumably making him Sidious' new apprentice, presumably making him Darth Tyrannous (assuming that name is true, of course).
So, if Lee is playing the new Darth, and that pic is also of the new Darth, wielding a sabre, we have a direct link. Granted, this is hardly conclusive proof, but it's a strong pointer.
Mind you, if someone gave me a good reason why it couldn't be so, it would not be the greatest surprise I ever recieved.
Remember, even though Select pictures are 100% official, we have no idea what they really are or why GL is showing them to us. Everyone assumes that the strange ones are just manipulated from what we will see in the film, we could be very wrong. In addition, as I remember, the duel select picture was taken very early on, and the fights were nearly the last scenes to be filmed.