No, I've never seen it and there's a scientific reason. You know the brown stuff between the tiles? And you know how things contract when it's cold right? So because the brown stuff and paint contact in different paces, the paint would crack and it would look really ugly (it would even look pretty bad before it cracks) Just replace the tiles with the colour you wanted.
Yes, there is tile/ceramic paint- several brands- all stocked by home improvement stores. The key element is the prepping. The old tiles and grouting need to be clean -and then cleaned again with the manufacturers suggested cleaner. You can decorate tiles, or change the color of the entire wall. Once the paint is dry, it is waterproof . It takes a bit of time, but with care, you should be able to do almost all the cleaning prep the day before and then just do the final cleaning and paint on the project day. Worst case, do one wall at time. It does not hurt to practice the entire process on one tile- preferably the tile hardest to see when you are on the outside looking in.
