This is complex, because EU-inspired legislation and pain-in-the-arris lawyers who keep worming away finding loopholes to exploit mean that UKBA has to keep changing the guidance on who can do what.
Your starting point you should be reading here.
http://www.ukba.homeo...on/partners-families/
I have had some involvement with this organisation in the past, I am not aware of policy that can cover the situation that you describe (but I don't claim to be have exposed to all the rules).
The concept of sponsorship that I know about involves businesses sponsoring a non-EU employee and it uses a 'Points System' to establish the value of the role / individual that would be fulfilled. None of this extends to the spouses of the sponsored individual, as far as I know.
Unless someone else in the know can respond, I think you are going to have to make an enquiry directly with UKBA - or there are paid-for immigration advisors you can turn to. You should not have to pay a fee upfront for advice.