Why would you need a special shelf dedicated solely to holding a simple cable box? Before the advent of thin LCD and plasma televisions, it was quite common to place one’s cable box on top of the TV set. This is no longer possible due to the thinness of current flat screen TV’s, and this is why you might find yourself needing to mount a small shelf to the wall, just below the spot where you have mounted your flat screen TV.
I like the black glass of this model, but I’m not crazy about the brace under it:
Wall mount cable box shelf pictured: Mount World 1431 Glass Component Shelf for DVD player, VCR, cable box, satellite, PS3, XBox, Wii and Video Accessories
If you are going for a minimalist look, you may want to pick a shelf that will be only slightly wider than the cable box. Or you could go for a wider shelf – one on which you would have the potential to place more components, if the case ever arose. Don’t forget that there will be wires dangling from the cable box.