It can't be done with out hacking the game (modifying the client) somehow.
Some of us have looked at the layout. It's setup in a specific way so you have your
5x slots and then your quickslots (usually for potions), etc.
The lowest level layer we have access to from the Lua API are client binds.
See these:
Slot API
The method there to set the ability slots is "SlotSkillAbilityInSlot()".
You can indeed use it to place your abilities into the usual slots but it will not allow you to set anything
outside of that legal range.