With the mouse (aoe) casting, I use Innerspace with the use of Repeater It's a program developed by Lax (more detail here).

With the repeater there is a pass mouse (so now is passes the mouse clicks to all toons) key. Well I bind that key to a button on my 58Xkeys and I have a macro on the same button in game that does /script SetView(5);SetView(5); <---- that tells all the toons to set their view the same so it's easier to control the mouse click, if not, they would all be looking in different directions. Then either have the same button do /cast Blizzard or /cast DnD and there you go... There is an IRC that can go further in to detail on it right now, just winging it off the top of my head right now (sorry pressed for time).

You can use the hardware method if you wish, I hear it's just about the same, better or worse (I have no idea). For that you are looking in the wrong place. Also, you can use keyclone and a marco or two (I can't remember what it is, but I think this might be it AOE CASTING )

To me, it's still a little cluttered, but I will work on it. To many randoms that could be combined into a /castsequence...

As for the addons (full list?) I can't remember, I will answer that when I get home from work.