In 2009*, the Dallas Cowboys put up in AT&T Stadium some videoscreens that measured 160 feet across and 72 feet high. Converting that to inches and applying Pythagorean methodology, we find that this yields a diagonal size of... 2,105 inches. Not yet available for home consumers, but still. Frank would be pleased.
Also note that there are several stadium screens even larger in scope-- The Safeco Field screen is 2,500 inches, and the brand new (more or less) Reliant Stadium screen is a whopping 3,382 inches diagonally (a bit shorter but a lot longer. Widescreen, donchaknow.). There's also a race track in Dubai and a speedway in N. Carolina, but I don't have exact confirmed numbers for those, and I don't think it matters enough to track them down. I'm sure in a couple of years there'll be another bigger one somewhere else anyway.
*"Frank's 2000 Inch TV" was released by Weird Al et. al. in 1993. 16 years ain't too bad to make something this hyperbolic happen.
Partial source:
http://stadiumblog.dallasnews.com/tag/guinness-world-recordsOther figures from "Bigger in Texas", Caleb Hannan, Wired, October 2013.