I installed one of these Sentronix motorised remote control wall brackets for our 60" TV about 6 months ago.





Jaycar sell these, not expensive, rated to 70kg or so I think, 60" LCD weight was <30kg.
But the fixing plate screws are at ~75mm centres horizontally, single-stud mount isn't going to work unless you've got a very small TV.  I had to remove wall lining to fit a double stud.  Those screws are about 8mm x 65 tek screws with hex/posi drive heads.  There are 8 of them holding the bracket to the studs.  They came with the kit.  Before attaching the TV, I swung my full weight on the motorised bracket to make sure nothing budged.  It supports my weight no problems.  While doing the stud, I ran conduit down the wall between two flush boxes with face plates on them designed for this purpose.  A bundle of HDMI cables etc go down behind the TV and come out at skirting level.  I was going to whack HDMI faceplates in, but as I'll replace the TV sooner or later, I'd rather have some way to easily re-run hidden cable rather than risk having to re-do the wiring later.  
Had to buy HDMI flexi angle adapter plugs for the TV, as plugs/cable on normal HDMI cables hit the wall.
The instructions for setting up the Sentronix bracket were pretty hopeless, the servo motors drive the gearbox via toothed belt, designed to slip if the TV hits an obstruction when moving.  If this happens, or if you "force" the position by hand, then the position sensors in the unit get out of whack, and it needs to be reset to "relearn" the rest position against the wall and maximum swivel angle.  Until I realised this, I was ready to give up, throw the thing back in the box to take back to Jaycar.  There should be a big warning on the box - "installing this device will cause severe headaches, frustration, and foul language".
Sorted now - after much more effort than I expected.
There's a small IR remote receiver stuck on the bottom of the TV bezel, wired back to the Sentonix mount.
At "rest", the TV sits flush on the wall - just as flush as any fixed bracket.  
There are two programmable buttons on the remote - for preset swivel positions.  I've got one for "left" the other for "right" to suit seating positions in our lounge.  Press the button, and the servo unit rotates the arm out from the wall, once extended it then rotates the TV, about 30 deg (in this case - you'd get more rotation angle with a smaller TV - the "learning" program when you set it up rotates the TV until it touches the wall, rotates it back just clear of the wall, then saves that setting).  You can tweak the position with arrow buttons on the remote, save that new position to the programmable button if you want.  Or not using the programmable buttons, just use the direction buttons.  There's a "home" button, which returns the TV to rest position flush against the wall.  Sometimes we'll use it not rotated, but extended so that the TV sits out about 300mm from the wall - for closer viewing.
With the multitude of issues experienced in setting this up, I wondered what the hell I'd done this for - perhaps the nerd factor exceeded the geek value.  However, it's become normal - we use it all the time.  It's very quiet in operation, a slight whirring sound from the servo motors, and the TV "levitates" itself from the wall and sets itself in position, prompting quite a reaction from people who hadn't seen it in action.  I've politely declined requests to install these.  The need to mount them on to a double stud puts people off.  I doubt that pro AV installers would want to have anything to do with the things, as they could be quite a can of worms.  Probably not a great idea for homes with young kids - not because of any danger, but if they play with the thing, you'll probably need to be running the re-learning program on it all the time.