Actually, you can freely move skills such as 'Guard' and 'Refill' to wherever you please by using text commands. For example, to move 'Refill' to the very last action slot on the action bar (third row, last column) you would type in: /eaction 30 "Refill"
You can tie this to a macro as well. However, there needs to be a much, much easier way to do this that doesn't rely on text commands and makes is far more streamlined.