Leandro from the Futurama Madhouse (TLZ), posted the page 76 of Wizard Magazine with a review of the Beast with a Billion Backs that included some awesome images created by the show's animation team at Rough Draft Studios in California. Well, there's an amazing article that talks about those images and an interview with the 5 members that created them:

Derek L. Thompson
Assistant Director

~ I chose Leela because she's tough yet feminine, alien-looking but still appealing. She can be tough for artists to get right; she's very subtle. ~

Dwayne Carey-Hill
Director

~ I liked the idea of seeing the Professor lost in his imagination. He's an insanely brilliant, crazy old man with a laboratory and a spaceship. What's not to love? ~

Crystal Chesney-Thompson
Retake Director + Layout Artist

~ I love that she's a strong female character [..] Then I thought, "If I were Leela and wanted to do a little ass-kickin', who better to choose than Lrr, Morbo and the Huge Gelatinous Blob?" ~

Peter Avanzino
Director

~ I like to think I had something to do with their creation. [..] And what can you say about a robot who loves stabbing things? I love how frantic Roberto is. ~

Stevan Wahl
Assistant Director

~ I can relate. You see, Zoidberg is an outcast in a band of misfits [..] He's like Charlie Chaplin, Henny Youngman and Curly of the Three Stooges all trying to wriggle out of the same ill-fitting lobster costume. [..] (We) both share a great love of eating and dumpster-diving. ~

There's a lot of more info at the Wizard Universe article called: Live Nude Humans! posted by the ToyFare Staff. Also, in another Wizard Article, there's a parody image of the Futurama Crew blended with the Hellboy characters, created by David Au, check it out over here.