Well, its all down to taste, but the first thing Id say is not to buy those ones from Maplin, but instead get them from Farnell (www.farnell.com). Farnell sell the ring illuminated version of these buttons which Maplin dont sell, and personally I think they look excellent. See this thread for a picture.
you should be able to run the LED by soldering to where the LEDs in the keyboard used to connect, but that will only give you control of 3 of them. Try searching the board for serial and paralell controllers for relays.