Well, today Mel Reynolds announced that he's in the running. The funny thing is, he already held that seat. Jackson took that seat after Reynolds vacated it. Reynolds, you see had some trouble with the law.
Reynolds held the 2nd Congressional District seat from 1993 until October 1995, when a Cook County jury convicted him of several sex-related charges, including having sex with an underage volunteer campaign worker. While serving time in state prison, Reynolds also was convicted on federal financial and campaign fraud charges. President Bill Clinton commuted Reynolds' sentence to time served in 2001.The story says he "no longer has to register as a sex offender".
I guess that makes him a valid contender.