@bside:

i could try it form scratch:

you only using a dual boxing-setup, so lets say the following modifiers will be the ones who idetify which one is leading:

ToonA: ctrl + key
ToonB: alt + key

First of all you do need two sets of keybindings one for 'assist' the other for 'follow'.

Say we wan't to bind the 'assist' to '1' and the 'follow' to the char left of '1' ('^' would it be on my german keybord, on an english one it would be diffrent).

Keyclone-Setup:

Create a keymap (keymapA) for toonA with the following hotstrings (and save it):
^ ---> follow.ToonA
alt + ^ ---> follow.ToonB
1 ---> assist.ToonA
alt + 1 ---> assist.ToonB

Create a keymap (keymapB) for toonB with the following hotstrings (and save it):
ctrl + ^ ---> follow.ToonA
^ ---> follow.ToonB
ctrl + 1 ---> assist.ToonA
1 ---> assist.ToonB

-Create a command in keyclone to start the wow for toonA in the region you want it and specify that it should use keymapA.
-Do the same for toonB with keymapB.
-start your wows with the two specified commands.

WoW - Macro-Setup:

For follow create this macro, with ToonA = name of your first Toon and ToonB = name of the other.
/stopmacro [nomod]
/target [mod:ctrl,nomod:shift,nomod:alt,target=ToonA] [nomod:ctrl,mod:alt,nomod:shift,target=ToonB]
/follow
/targetlasttarget
Drag this macro to a button, and create a keybinding for '^' on both toons.(make sure you have not bind alt+^ and ctrl+^ to another buton)

For assist create the following macro (with the names of your toons)
/stopmacro [nomod]
/assist [mod:ctrl,nomod:shift,nomod:alt]ToonA; [nomod:ctrl,mod:alt,nomod:shift]ToonB
And bind it on both toons to '1' (make sure you have not bind alt+1 and ctrl+1 to another button)

This is the basic setup, if you want all toons to follow your active toon, simple hit '^' (without any modifiers), if you want all slaves to target the target of the master hit the '1'.

if you then want to do a simple cast by pressing '2' simply darg the spell you want to cast on the button you have bind the '2'.
Or if you want to do a /castsequence create it as normal an drag it to the corresponding button (same for petattack and).
For your hunters you could f.e. simply drag 'Arcane Shot' to '2'. For the warlocks a /castsequence might be better.
Be aware, that you can use all modifiers and reset-conditions in your dps-macros in this modified approach.

For example my warlock uses the following makro on his 'dps-button':
#showtooltip
/castsequence [nomod] reset=target Immolate,Shadowbolt,Shadowbolt,Shadowbolt,Shadowbo lt,Shadowbolt,Shadowbolt;[mod:shift] Curse of Elements;[mod:ctrl] Corruption
My 70 hunter uses the following lame macro as a braindead-dps-macro (which you have to adapt for weapon speed and talentspec)
/castsequence reset=3 Steady Shot,Arcane Shot, !Auto Shot, Steadyshot,!Auto Shot
/cast [nomodifier, target=pettarget, exists] Kill Command
Hope i could help.