Has anyone thought about contacting McDonalds about this, as it is [vaguely] relevent to them regarding the rights to use a single letter as a logo. A few years back here in NZ a big corporate brewery (the one that successfully trademarked the word "Radler", despite it being used internationally to describe a certain style of beer) tried to bully a small but iconic brew-pub to stop using the name "Summer Ale" for the summer beers they were brewing, despite the fact the pub had been using the term for many years before the big brewery decided to stop using it. The other big corporate brewer here picked up on it and actually jumped in to help fight the battle for the brew-pub as they felt it was settling a bad precident by allowing such a term as "Summer Ale" to be trademarked by one company, and they won!
Moral of the story, you knever know who will stand up and help you fight...