Baz, don't know if this is the correct answer, but i play pool on the Miniclip site (graphics are really good) and they used to have a 'quick fire' game whereby the player was given 5 minutes to pot as many balls as possible. Each time a player was 'on' the last ball, the remaining balls would be re-racked. If a player potted the white, 30 seconds was knocked off the time. Pot the white 3 times and it was game over.
Unfortunately, Miniclip have altered this game so that it is no longer enjoyable, imho, so i stick to the regular 8 ball and 9 ball games.