Check out this discussion of soundalike songs. I can agree with some of them, but others are quite a stretch. At the end of the article is a link to an entire site devoted to the quest of finding soundalike songs.
Reminds me of "Spot The Similarity," a feature on a weekly show called "Psychedelic Sunday With Russell Carey" I used to listen to in Columbus, OH in the 80's. (Yes, I ripped off that title for my weekly blog post/podcast.)
I used to keep track of soundalikes, but I've been lazy of late. I can't even think of one at the moment.
Got any you can think of?