I still contend that Shane Watson is the man for the job. And all you guys denigrating his bowling; when he is given a chance and really lets go, he can be as quick as anyone.
Just be patient. You're all writing him off too soon.
As for the second allrounder's spot, give it to Mark Higgs. Whilst Australia hasn't had decent pace-bowling allrounder in quite some time, they've NEVER had a decent finger-spinning allrounder, especially one who can hit the ball as hard as Mark Higgs.