I read posts by jack earlier about sending in your I-751 early so i decided to check it out since my wife will be doing just that in a couple months. I found this on the immigration.gov website. So after reading this nobody should be left in limbo if they file on time.
Will I Get a Work Permit?
As a legal permanent resident, you should have received a permanent resident card. This card will continue to prove that you have a right to live and work in the United States permanently. If you file your BCIS Form I-751 (Petition to Remove the Conditions on Residence) on time, the BCIS will extend your conditional resident status for up to 12 months while your Form I-751 petition is under review.