Many years ago I used a program called Chess Vision. Instead of showing the current position of the pieces on the chess board, the position from 6 moves (or any other number of moves) ago was shown. This forced you to keep a mental image of the moves that had been played so far. The idea was that doing this would help strengthen your read-ahead skills by helping you practice visualizing future positions and making decisions based on a position that you couldn’t actually see.
I can see the same thing being useful for sharpening reading skills for Go. Does anybody know if such a program exists for the game of Go? If not, what other suggestions do you have (besides life and death problems) for practicing reading skills?