A little while ago I received a commission to convert and paint some themed chimeras for a Praetorian Imperial Guard force.
One was meant to be the chimera for an Ogryn unit. This one shows battle damage from the inside, since the Ogryn, it seems, are afraid of the dark. You can't see it quite as well from this photo, but the back door also shows signs of abuse:
The second chimera is for the psyker squad. Rather than show the extra battle damage, this chimera is covered with scrolls, purity seals, rune plates, a few books and even a couple of eyes.
I'm still not sure if those embellishments are meant to protect the psykers from warp energies, or if they're there to protect the rest of the guardsmen from the psykers.