Those commercial displays are nothing but heavily stripped down TVs with anything unnecessary to being a advertising display removed. and maybe a tiny, grossly overpriced and heavily cut down computer built into it to run the slideshows/menus/whatever.
also, TVs in a certain size range are generally cheap because manufacturing has gotten to the point that each mother can produce a ton of screens for it. and the reason that cheap range size has gone up over the years is because improvements in the printing technology and the size of the mother glass.
This.
I am so sick of that goddamn song.