I have some of those same chargers, but they are pretty useless as 4 ports since they dont do per port current limiting so things show charging, but often are not actually charging as 2 or more devices on it battle it out for the limited current available. One device at a time works fine.
Belkin does a 4-port USB charging array: http://www.belkin.com/conserve/valet/
but it doesn't have enough juice for an ipad, so you will need additional chargers for that too.
My opinion is rather than spend money on trying to get efficient electrical outlets etc - which can easily be obsoleted - is to find a space where you to wish to renovate and make a hideaway shelf.
Plenty of power options, and a lovely door to close so you never see it. And nothing obsolete in the walls - and believe me, the pace of innovation is such that you'll be glad that the humble 230v plug hasn't changed in donkeys years.
I ended up getting a Sockitz after seeing it on this thread, to install in my headboard for charging my phone overnight.
My thoughts: - I think the shutters on the USB ports switch the usb charging circuit on/off so it really is zero power consumption when no USB cables are plugged into it - As previously mentioned, the blue light coming out from the USB sockets is a bit much for the bedroom if you like things perfectly dark for sleeping, but it looks like it is a standard LED (not SMD) so easy enough to open up the device and remove the LED by sniping the leads
- Generally very impressed, its a nice solution and well-built