EDIT: Since these macros seem to be of help to a number of folks, I've added more instructions for how to set the "2 Step" up in ISBoxer here:

If you are using Lax's "FTL DPS Keys" keymap, you already have a "DPS 2" mapped key that simply sends the keypress of a "2" to all windows when you press "2".
Create another mapped key within "FTL DPS Keys" called "2 Step" that is also called when you press "2" but has two steps - the first sends "2" to all windows (exactly as above), while the second step sends ";" to all windows.

Now all you need to do is set up a new mapped key in your "Control" key map. I called mine "2 Step Toggle" and associated it with the "Insert" key. It will have two steps in it.
Step one has 3 actions:
1) A new mapped key state action (one of the options when you add a new step) that toggles the "DPS 2" mapped key within "FTL DPS Keys" to On
2) A new mapped key state action that toggles the "2 Step" mapped key within "FTL DPS Keys" to Off
3) A popup text with a message like "2 Step Turned OFF"
Step two has 3 actions:
1) A new mapped key state action that toggles the "DPS 2" mapped key within "FTL DPS Keys" to Off
2) A new mapped key state action that toggles the "2 Step" mapped key within "FTL DPS Keys" to On
3) A popup text with a message like "2 Step Turned ON"

That's it! Use "Insert" to turn your toggle on or off.

Attach the sequence macros to your "2" key in WoW and the proc macros to your ";" key in WoW. Done.
really interesting idea, thx a lot for share

i m trying to setup a viable method to manage multi-independent-targets, temporarly disabling ftl and your idea is good base