re: How can I hide all these wires?

build a small box with no back on it to put your cable box on it paint it if you like but then you can stuff all the wires into the box but it looks like a stand for your cable box or you could build another shelf just above the other one use a filler board on the front, but leave a gap at the back and stuff it all in the hollow shelf.
zip tie it all together to tighten it up befor your start stuffing cutting a false back can be difficult and it wont trim out very well but you could use a spacer block to keep it off the back of the cabinet evenly and attach it with velcro.