we are here on a 457, as the partner of the main applicant i have full work rights in australia and can set up my own bussines. does anybody know if i can then go on to sponsor employees to work for me ?

Nope!!! You have to be an Australian employer to do so, registered as such and then accepted as a 457 sponsor. You are on your spouses Visa and as such have a finite time here, you can not guarantee your 'sponsored employees' any period of work past your own visa expiry date so its therefore not only unworkable but also unethical.