Here are pictures of the two air vents in my 2008 Elite. You can see one is located on the wall as you exit the trailer, and the other is in the galley area, on the wall to the left of the sink. They provide passive venting from the rear of the space containing the oven. Not sure of a source for the vents, but you get the idea and should be able to find something similar. If you are particularly handy and inspired, consider a tiny switch activated fan mounted behind one of the vents which could turn it from a passive to an active heat protection.
Good luck! Be sure to post pictures of your finished project.