keymaps are useful. map the keys normally for each wow.. and then map them as you see fit.

ie:
you need an opening salvo... hit 4.. which will be different things to different classes... as the 4 would get changed into a 5 for the warrior (charge) .. a 3 for the priest(shield focus) and fireballs for the mages (f2)

if that sounds like what you need, just let me know and i'll see about getting you more info