Finding bloated indexes?

Is there a pg_stat_* table or the like that will show how bloated an index is?
I am trying to squeeze some disk space and want to track down where the worst
offenders are before performing a global REINDEX on all tables, as the database
is rougly 400GB on disk and this takes a very long time to run.

I have been able to do this with tables, using a helpful view posted to this
list a few months back, but I'm not sure if I can get the same results on indexes.

Thanks

-Dan