Yes - should work. We've done this...

You need to use an active Dual-Link DVI adaptor to connect to the X4
But - do test the playback and ensure the movies are running at the correct speed - don't just rely on the frame counter... check against a real-time source.

I would use the DVI-DA option rather than 2x Datapath X4 as will put less load on the system (and probably be a cheaper option)

However, the image rotation can be done in catalyst with the mix windows... you don't have to do this with the X4.

Whatever you do - TEST TEST TEST... MacPro 6,1 and mavericks are new technology and we are finding new idiosyncrasies every day!...