you could try a product like this:
http://www.tvwallmountsreviews.com/videosecu-tilting-tv-mount-extra-large-articulating-swivel-wall-mount-for-lg-36-37-38-40-42-46-47-plasmalcd-tv-with-free-7-ft-hdmi-cable-1vh/
however, keep in mind that this is noted to sag (from weight) and you need to connect it to a load bearing surface. because of the large (26"?) clearance from the mounting surface forces implied will me multiplied. this means that maybe you dont want to connect it to anything short of a wall as you could risk for tv for naught.
i wouldnt trust a single arm type unless it was built very heavy and connected direct to a wall. flat-mount types typically offer a few degrees vertical tilt, horizontal pan, and if you are lucky.. a...