if my Excel tip doesn't work for you, you can probably use KM to create a loop to copy the current cell, check if it's empty, and move down using the Down Arrow key if the current cell is not empty. Then when you get to the first non-empty cell, move up one. Then we are at the bottom. To select everything upwards there might be a special key sequence in Excel, but if there isn't you can press SHIFT-UP as many times as you previously pressed down.
That's the approach I would use. Is that a good lead for you? I'm afraid I need to catch some sleep now.