For those who may be looking for some decorative shelves that have hidden mounting hardware, JYSK has some nice ones that have a prefinished textured woodgrain surface, I bought 2 of the 23.5 inch (60 cm) length and color sanremo last week and installed them in my kitchen. I have found that such shelves seem to be hard to find in other stores. They are finished on all sides (including the bottom) except for the wall side.
The shelves are approx 10 inches deep and 2 inches thick (hollow) and there are a few lengths available and a few colors available. They have a listed weight limit of approx 10 pounds but seem like they could handle more,
The mounting system consists of a flat bar with 6 screw slots and 2 attached round tubes that fit into 2 round holes/tunnels in the back of the shelf, i.e. a u-shaped system with the bottom of the U against the wall. The instructions say to use 2 or 3 screws (not included) to mount the bar to the wall and they recommend that one should be in a wall stud. I my case, there were no studs where I needed to mount the shelves so I used 2 toggle bolts for each shelf in order to mount them securely to the drywall. I am using the shelves to hold some glasses and coffee mugs. Two small screws (included) on the underside of the shelf attach the shelf to the metal bar to prevent the shelf from sliding off the hidden mounting tubes.
Very easy to install, great colour and look great.