You could tie perltidy to the mercurial commit hook, and use that as an automatic checker for style before commit.

We have so much old code in various styles, this would be much easier than tweaking things by hand to make everything conform, and once you've gotten past that first big burst of formatting, you could run it again and see any style issues in any new patches.

And yet, and yet...

 

if ( $foo )
{
  bar();
  quux();
}

 

if ( $foo ) {
    bar();
    quux();
}