Thanks for you feedback so far, guys! Sorry I'm only responding now.
@Ralston18 A large what? I think there is a word missing that your 4'x4" dimensions were meant to relate to.
I think placing the screen inside the wall is really going to cause more trouble than it's worth.
As regards tiltability, I don't think this is going to be a big issue in my case. The room is small (62 sq.ft.) and has only a single north-facing window that's not terribly big (maybe 2 1/2 ft. wide, 3 ft tall). The screen will be mounted on the south wall and this wall is also the only one with a door. Lighting in the room is most likely going to be "artificial daylight" - to be honest, I don't know much about this, but my optician recommended it, it's basically large flat lamps that cover most of the ceiling and light the room very much daylight would, which means that light is distributed evenly without bright glares. Do you think under these circumstances it would still be important to be able to adjust the screen? I have attached a part of the architectural sketch for the office, in case that helps.
I'm going to have a couch / convertable bed in the small office (this is a very small apartment, I might add), so maybe it would actually be a good idea to use a fairly large screen, so we can also use it as a TV. The distance from the south wall to the north wall (south is up on the sketch) is only 7 2/3 ft., so no idea what size would be recommended. I've never actually owned a screen larger than 22", I believe. I've used an LG Flatron 2286 for the last 9 years but now it has finally given up the ghost. I also don't have a TV, so I know very little about such things. From what I've gathered 27" seems to be "standard" nowadays? Which is pretty funny for someone who grew up with a 14"!
As regards the legal requirements for working with the wiring: This apartment is located in Croatia, where nobody seems to give a damn what you do with electrical installations inside your home. As far as my research has taken me, the only thing that is regulated is gas and that is probably a good idea, too.
Thank you for the Amazon link. Do you have a recommendation for a mount as well? This might be a really stupid question, but how do you actually get the thing on the wall? I mean... you can't but a screw through your screen, right?