Need advise regarding small bookshelf monitor

Check out the North Acoustics small monitors, Spirit and Kitty Kat Revelator, made specially to go near the wall.

http://www.northacoustics.com/

If you mount in a bookshelf or entertainment system - do yourself a favor and install with a picture frame around the baffle and integrate into the walls in a flush mount fashion. If you do not then you will surely face strong edge diffraction issues. (This also means you need a forward facing reflex port in your choice of speaker and to fill any void space around the speaker with acoustic batting)

Alternativley use a wall bracket with a long extendable arm so that you can bring the speaker well forward from the cabinet shelves by a speaker length (even if you only do this for serious listening).

NHT Classic threes

How much do you want to spend?
Tobias speaks the truth, North Acoustics speakers are made for this type of application.