Check out the Sonitus multiband compressor (don't laugh). If you're using the brickwall to squash the sound and get that pop music thang, it doesn't really do the job...Waves L-series stuff is my preference there. But, if you enable the limiting option on the master page, you can push that puppy pretty hard, like +6dB over 0 at the input. The output ceiling is an automatic -0.1dB.
Its best use is catching transients, like if you have something that's pretty much ok and you just want to make sure you don't get any overs.
But the ceiling restriction isn't necessarily a restriction...it helps discourage intersample distortion, which can show up when a project hits a duplicator and cause it to get rejected for overs. If you really want to max out, you can render with the brickwall and normalize to 0.01 dB or whatever.