For EB-1a, you do not need any job and you do not need a sponsor to petition for you. You petition yourself. In I-140, many places just leave blank. I did it in september: my EB-1a received 9/7/05 and approved 9/14/05 at TSC. I got BS and MS from nonkey universities in China and Ph.D. form a small university in Australia. So I believe many many people can get EB-1a approved. Do not scared by the so-called extraordinary ability described in the requirements. Many many people are of such ability in the immigration context.