I’ve just started following the culture+typography blog which is a regular source of interesting observations on lettering and signage in the public sphere. Above is an image from blog author Nikki Villagomez from this post about an entire building wrapped in a ghostsign for Liberty Tire. It is a great discovery from Cincinnati, and could rank as another world record contender. (On that topic I also found this photo on Flickr which also has a shout at the title.)
Another post of note from culture+typography is this one about the way that some ghostsigns’ paint tends to peel rather than just fade. The example of this from the UK that always sticks in the mind is the one for Strongs Meat in Stoke Newington.