Along with olipics, I too am using Pitbull with the toons sorted alphabetically. The configuration is 'locked' so the unit frames cannot move around unless you go into the config mode. Also, every account has the same pitbull setup with the party bars in the exact same position.

When my tank uses button4 (the left side mouse button) HKN checks to see if my mouse position is in the range of the name plates. If I am in fact hovering over the name plates, then it sends the current mouse position along with the key 'd' to the healer. The healing slave receives the current mouse position along with the button press 'd'. On the healer 'd' is associated with a macro that says /cast [target=mouseover] Healing Wave. Since the name plates are in the same range on the healer, as they are on the master, the shaman heals whatever target I was hovering over. Currently I have a similar broadcast for shift-button4 which sends 'shift-d', which has chainheal.

If my tank uses button4 and I am not in the name plate range, then I can send whatever I want to whomever I want. It's very likely that I will have button4 healing the tank (standard /cast [target=Strong] Healing Wave), while if button4 is in the name plate range then it is healing whoever I'm mousing over.

Note that this was just a test case and I will be refining my key bindings and how to set everything up. As I mentioned before, this type of functionality can be used for more than just healing. Since I have my party order the same on master and slaves, and their target is directly to the right of their nameplate, I can also define that range. For instance, I may put some functionality where if I'm in the party-target range and I push 'shift right click' then it tells both the pally and the shaman to cleanse the mosue-over target (so that magic, disease, curse, and poison are all removed with one button push). Also, since I am looking at what my party-target spells are being cast, I can earth shock them while controlling my pally without ever changing my target.

The nice thing about mouseover is that I don't ever switch my target. My moonkins will gladly keep casting away at my tanks target while my shaman heals whatever name plate I click on. I think eventually this will allow for easier crowd control and micromanagement.

I feel some automation questionis/complaints coming on and I look forward to a good discussion I personally don't see a problem as I am pushing one button on the master and sending one button to the slave. The only difference is I am also broadcasting my current mouse position, which is no different than placing AoE spells or anything that uses mouse functionality.