I don't understand why having several boxes is a problem for the swivel wall mount, but not for a ceiling/etc mount? Either way you have to have the boxes somewhere, and I assume you didn't intend for them to be hanging from the ceiling..
The wall mount is simple. You can use a mount like this:
Put all your other equipment in the wardrobe/closet. Get a couple long HDMI cables (or whatever you need) to connect to the TV.
Alternatively, you can also get wall-mount shelves for mounting equipment, if you don't mind seeing it sitting out (and of course, you can use any random shelf from anywhere, if you like):
(source: monoprice.com)
You can use an IR Repeater so you're able to control the devices even if you can't see them.
You can use some kind of cable wrap or wire raceway (eg Wiremold) to route the wires over (which looks WAY neater than just having a bundle of wires):
Alternatively, if you're really adventurous, route the wires through the walls (and/or ceiling). Since you're on an exterior wall this would be a huge pain (due to vapour barrier and insulation), and personally, I wouldn't do it.
