Taking two ideas and combining them is just one way to generate new and unusual ideas. Take for example, this guy:
From the Instructables site via Neatorama, we can see the value of taking apart common ideas and reassembling them to create something new. This tactic is valuable not only for new product development, but for creative problem solving as well.
One year, one of my teams decided to include two landmarks in their presentation: Ayers Rock and the Golden Gate Bridge. The props were to serve as an obstacle for their vehicle. I don't remember the exact details, but one obstacle had to be (I think) at least one foot off the ground while the other had to be at least two feet off the ground. The fiddled and fuddled with two different obstacles, frustrated with the tight space they had to work in, until a light went off. Bing! If they made ONE obstacle, at least two feet off the ground, it would suffice for BOTH requirements. And so, their two props became one; from one perspective the audience could see Ayers Rock, but when the prop was turned around, the Golden Gate Bridge appeared. It was a brilliant solution and an excellent way to meld two ideas into one better idea.