That's hilarious. I can just imagine the person with the tatoo wandering around and periodically being accosted on the street by typographers: 'Did you know, that A is backwards?'

I used to photograph backwards and upsidedown letters (A and X are the most common), but gave up when I realised just how many examples there are. My favourites were always the ones that were really permanently installed, preferably in some very expensive and difficult to correct medium, e.g. carved in stone on the side of a pretenious menswear shop. One of the best has to be in Brompton Oratory in London: there is a text in gigantic brass letters running around the inside of the base of the dome, and one of the X's is upsidedown.