This is a really popular weapon loadout for a Carnifex. It takes all four upper limbs. Two twin-linked devourers put out a ton of shots, and they get to re-roll to-wound.
Anyway, a client sent me this picture. It's made from the crushing claw arm from the carnifex kit, and a few devourers and green stuff. Very nice.
At Adepticon 2007 I saw a guy who made a quadrifoil gun to represent two twin-linked devourers.