Are you talking about like, creating profiles for your abilities? So that if you select Profile A, you automatically have all of Spec A's abilities? and then another for PVP or whatever?
Not 100% positive, but I'm fairly certain Bartender4 can do that for you.
Isn't it better to have as similiar keybinds in different specs/roles as possible?
For example back then in TBC I used to think that when I am not needed to heal too much in BGs I will just use different action bar that will replace my healing spells on 1-6 etc with dmg spells. I did but in the end its a mess.
Just using all keybinds possible ctrl/shift/alt + 1 through 6, q, e, f, g, c, x, y... is the best way imo.