"Is it possible to have a BV7-40 in one room, and have a projector in another room, and use the cinemafunction."
Yes. But you can`t control the system from 2nd room, because there is just one IR eye.
"Thinking of having av bv7-40 with 7-2 in one room, and projector, BL9, BL7-4 and BL3 in another. Is it possible to use the tv and the proector at the same time, with different sources?"
No. FORMAT 0 (or Cinema button on Beo5) toggles beteween TV- and Cinema mode.
"Also to different soundsetup at the same time?"
No. It also switches between the two sound setups.
This was discussed some time ago also in Scandinavian Forum - if I remember correctly.
Stefan