After serious thinking NoSpam wrote :
Pretty simple really ...
2 pieces of aluminium angle screwed to the holes in the back of the
display/TV. 2 pieces of angle fixed vertically to the wall, spaced so that
the angle on the back of the TV nicely slide between them. Holes arranged in
angle so that a bolt through each pair acts as a top pivot, if necessary a
strip of metal at the bottom to give a tilt control (but I experimented first
and decided that tilt/pivot wasn't necessary so I just have 2 lower bolts).
The big advantage is that the TV is almost flush to the wall and totally
solid - also, it cost about £3.

Looking to mount our new 42" Plasma (28Kg) across a room corner, I'm
thing of using Dexion angle.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk