I do that for one of my shamans, which is my raiding toon also.
What i do is I use 2 wow directories, one for slaves, one for my raiding character(and well my dk has another one too), for both copies I use bartender 4, on my slave I use bar 1/2/3 and for my raiding one I use bar 4/5/6/7, so every time i switch my buttons stay in the same spot on both clients.
The only thing that i need to redo every time is some kuey bindings, but that with bar4 takes about 5 seconds.