Well, I can think of one or 2 scenarios:
Smith, AB de Villiers, Amla, Kallis, Prince, Pollock, Boucher, Harris. Then one of these : Nel, Steyn, Hall, Morkel.
That will mean there are 5 batsmen, 2 allrounders (if Hall plays), a spinner and 3 quicks.
On the other hand, the selectors may just replace Gibbs with Jacques Rudolph. If that happens, I think Hall will sit out again to make way for 3 quicks: Nel, Steyn and Morkel. This of course assuming Ntini is the one who'll be rested for the PE match.
There is of course the small matter of keeping the politians happy. And that means this suggestions of mine will flow right out of the window....there are only 2 "quota" players: Amla and Prince...
They could always draft JP Duminy in...

Or perhaps just rest Polly...and not Makhaya.