Andy Biggs was telling me last weekend that "en banc" in the 9th Circus isn't really en banc. The 9th is huge, with something like 30 Judges on the panel. What they call en banc is really only about a third of the Judges, and can be stacked against the right by the Presiding Judge, who's a far-leftist whack.
AFAIK, it's the only Circuit set up this way, and it's begging to be split into two or three parts to get it to the size of the rest of the Circuits.