Opening repertoire for different levels I wonder, is there any book or article on what openings are good and appropriate for different levels, as it's done in the 4th volume of John Watson's Mastering the Chess Openings and in this link http://www.uschess.org/content/view/11634/675?

And what are your recommendations for this question?
There is something to be said for choosing mainlines from the get-go. I heard several strong players (for example Jan Gustafsson, Judith Polgar) say, that they wasted time by playing sidelines in their youth or that they had problems to master certain openings they had avoided for too long. (Gustafsson played 1…g6 and Polgar King's Gambit).

So if you are young and very ambitious it makes a lot of sense to go for openings you will never have to discard. If you look at the absolute top, even Carlsen's experiments with sidelines quite often completely backfire (Northsea Defense vs Adams, Pirc vs Naiditsch, Leningrad Dutch vs Wojtacek, weird gambit vs Saric, etc.).

But most of us never reach these heights and under Elo 2400 you can get away with all kinds of openings. So my choice is to play what I feel comfortable playing and from time to time mix in some completely new stuff so I don't get bored. I play some very shaky and borderline incorrect stuff, but I can't remember ever losing because my opponent just played "the refutation". There are always chances.