I suggest you consult an employment attorney. I changed the category of your question to employment law.
This response does not constitute legal advice and does not create an attorney-client relationship. Due to the complexity and ever-changing nature of the law and to the limitations of this forum, this information may not be adequate for your specific situation.
I don't know anything much about employment law, so I can not answer what remedies you may have in employment law.
I do know something about "tort"/defamation law. I would be very interested to know the particulars about who you ex-employers spoke with. Were they people who were not calling in for a job reference? Regardless of the fact that you did not steal from your employer, did your employer have a reasonable basis to believe that you had stolen? If they had a reasonable basis to believe that you had stolen and if the only people they told of their suspicions about you were people calling in for a job reference (there is a privilege from defamation liability at work there) then I would think that you do not have a viable action in defamation against your previous employers. Now, if they did not have a reasonable basis to believe you had stolen OR if they had spread their belief about you to people who where it is non of their business (not about job references) then you would have a better shot. The answer is all in the details.
If you want to discuss this further with me, send me a note. Attorney Jere Franklin Ownby JOwnby@OwnbyLawFirm.com