Mschere: Based on this academic study of "Setting a Judicial Agenda: The Decision to Grant En Banc Review in the U.S. Courts of Appeals", it would appear that the odds of an en banc review are pretty low.
Note 8, page 30
During the period of study, the circuits varied in the rate of en banc review from a low of approximately one en banc for every 1,000 panel decisions in the Second Circuit to a high of approximately 10 per 1,000 in the Eighth Circuit. The Fifth Circuit -- with 6 en banc hearings per 1,000 -- did not differ significantly from the all-circuit average of 5 per 1,000 panel terminations.