I have the Epson 5010 with a 2.4 screen size of 50"x120". The 5010 is installed in a hush box so its difficult to manually zoom an un-zoom when I change the ratio. So I have installed a motorization system for the zoom, the lens shift and the focus. See my thread:http://www.avsforum.com/t/1401911/diy-motorization-of-epson-5010
you can also see my cinema in my signature.
To answer your questions:
1- Yes, you can but the zoom and lens shift should be accessible. Fortunately, when you zoom the focus doesn't change.
2- No visual change in image quality from a seating distance of 11 feet.
3- This projector is really bright. I use it in cinema mode, low lamp. The projector is installed at ± 14 feet from the screen. If yours is installed farther away you will lose some brightness.
4- You can see a video in my thread. Its not long around 20 seconds.
You can also look at the Panasonic AE8000. It has motorized lens and memory and its almost as bright as the 5020 but the blacks are not as good. You can see some comparisons at Projectorcentral.com and at projectorreviews.com
I hope that Epson will have motorized lens with memory in their next gen.