Pitch One, Hit Another
"If your pitch falls flat, it's easy to blame it on an editor. Too easy. If your story matters to you, find a way to recast it and pitch it again so that the editors can see what you have. Don't drop the idea at the first obstacle. If you really have a good idea, it deserves more than a half-hearted pitch" (Grimm)
First of all, I always admire people's creative abilities when they pitch ideas for news stories, books, advertisements, magazines, etc. Not only do I think their creative abilities are a great talent, but also the time they are able to think up an idea and run with it is amazing.
From my own experience (although I have never pitched a news story), I find that suggesting one idea usually leads me to another interesting topic that I would rather write about, especially if I didn't feel completely satisfied with my first suggestion. An example of my own personal pitching (or at least anything close to it) would be trying to come up with different paper topics. Although they may fall from from newspaper article ideas, I may start with one paper topic and end up with another because of where the first one started taking me. Also, although I don't have an editor, I do have professors with different tastes. A thesis that might sound terrible to one professor may be acceptable for another.
Also, as the website mentioned, if I come up with a topic that I really want to pursue, I usually have to reword the thesis for it several different ways before it gets accepted.
I think pitching ideas for a news article would be an interesting way to see how creative you can be and also how perceptive you are to seeing different angles to an idea or story. Also, I think it would definately be more fun than pitching research paper topics.