Help with job change

[boilerdam]

I'm not sure if this is the correct group but I have an approved I-140 for 3yrs now. I work in the IT sector and want to change my project/client. I want to stick with my current employer with whom I have the I-140 already. 

All vendors I speak with want me to move over to their employer but I do not want to mess with my I-140. Any suggestions or pointers on how to find vendors willing to take contractors on somebody else's I-140..? Thanks for your help..!