Actually, with the dremel tool, it was very easy to grind the LEDs after they were already installed. Just had to be very careful not to let the spinning bits of the dremel's shaft touch any part of the player while I was doing it.

Don't have any photos to show you at the moment, I'm afraid. All I can say is that griding them made the light more diffuse at the expense of a slight reduction in overall brightness. I did not polish the faces of the LEDs, I left them rough-ground.