The One Ring reports that Guillermo del Toro confirmed on their message boards that he would have a cameo in The Hobbit, much like the ones Peter Jackson prepared for himself in the trilogy. Here is part of what del Toro said:
“I had a hand on the design of the creature and I will personally sculpt the appliances that will be applied on my face and hands. I used to sculpt the creatures for NECROPIA (my FX company) and I miss it a bit. I will have a line or two and die quickly.”
This was in response to a post about a German interview he did, in which he said:
“In The Hobbit I will play a small monster. I will transform myself in a small creature, not an important monster, just a type ‘background’.”
Small cameos are more about actually trying to find the director in the milieu. In this case he’ll probably be in plain sight, though hidden beneath a lot of makeup. I also enjoy small one scene cameos like Martin Scorsese had in Taxi Driver, though I’m not entirely crazy about a director inserting himself wholesale into a film, like Quentin Tarantino is apt to do, unless he also happens to be an accomplished actor who you’d be used to seeing in roles (Clint Eastwood would come to mind).