What size LEDs are being used? (I remember, about 5 years ago, there were SMT LEDs available in sizes as small as roughly 0.5 mm × 0.8 mm × 1.2 mm, or multicolour ones in 4.0 mm × 4.0 mm × 2.5 mm packages. I think Osram Sylvania was the manufacturer I'd used.)
I'm also pleasantly impressed by the fact that someone is putting all those Arduino-based units of clothing to shame.
(There are a few genuinely innovative ones, but for the most part, the novelty of a string of flashing lights in a jacket wore off a couple of years ago. Making it into a TV raises the bar.)