the team I support mainly (apart from stanley down here) - Rangers have card displays at all their euro games although the club dont pay for them - its purely down to the fans - each of our displays cost about £4k a time but they look good...see the links below to get an idea of ours...I think card displays are an excellent idea and add to the build up of a game....
http://media.putfile.com/villarreal-card-display
http://media.putfile.com/Villareal-display