Thanks to both of you for helping out!
I can just about manage 12 feet lens to screen if PJ is mounted on rear wall.
I do not aim for CIH or 3D, just a simple but good setup, and main reason to look at PJs is the fairly small size of TV screens.
The room will not be very bright, PJ will be used mainly in the evenings for movies, and I plan to use a TV for any casual or daytime viewing.
As for lens shift and rainbows, I really don't know what these terms are, I need to study this more.
I don't have any equipment yet, I am just trying to prepare a new apartment for possible install of PJ and screen, and I need to know it is possible, and where to put mounts and cabling.
As for budget, I haven't got a limit as such, but I don't want to spend a huge amount. That's why I posted in the under USD3,000 forum.
Any brands/models you can recommend for me to look at further?
And does screen gain come into this at all? I am probably also going to need an acoustically transparent screen, since it will at least partly cover the system and speakers.