I might as well go first
Screen: I have a Curved AT 2.37:1 screen 2250mm x 949mm. The curve is adjustable to optimize for pincushion correction.
The LCR speakers are positioned in the same horizontal plain with their cabnet tops at the centre of the screen line of the screen and where the L and R are just inside the 1.78:1 area. I did this so that the sound to image match would work for all ARs and not just Scope. Also real cinemas and dubbing stages have their L/R speakers there too, so I now hear what they heard.
The screen height si currently 600mm off the floor, but I would like to raise it to at least 800mm, maybe 900mm.
Projector: BenqW5000 with CAVX Aussiemorphic Lens (yes I have prototype MKIII in testing now). The projector is 1920 x 1080 DLP and delivers a spectular image.
Source: HD DVD via a Note Book PC over HDMI.
Seating distance: 2 rows where front row is just 2x the image height. Close but this really works well with a 1080 projector. Back row is just over 3x the image height and is elevated 300mm.
Other Audio: THX 7.1 processed DD and DTS. I use 3 identical LCRs with controlled Vertical directivity and 4 Identical Surrounds (Bipole) and a pair of Subs using Peerless XLS drivers...
Mark