This issue has come up from time to time and the answers are never good news. For video wall setups you need to avoid all but one off the shelf (or showroom floor) TV and look at commercial signage units. Your high end suppliers and theater specialists use that. Need an example?
http://www.samsung.com/us/business/displays/digital-signage/LH46HDBPLGA/ZA

These can be customized with apps and controls so that each display is independently controlled.
Bob