That would be an extremely odd book, but from what I read on agent blogs, such unusual pairings are not unheard of in query letters. Some agents want you to tell them who your book is like, comparing it to other authors so that they’ll have a ready comparison from the marketing divisions of publishing houses.
However, also based on what I’ve read, such comparisons can shoot you in the foot. I compared my urban fantasy to Terry Pratchett meets Charles de Lint. It STILL makes sense to me, but I think I’m the only one. I ultimately removed that from my query letter since I clearly don’t get the comparison game. I’m just sticking with “urban fantasy” even though my writing group has suggested other writers to compare myself to, but I’ve never read those authors, and I can’t see comparing my writing to an author I’ve never read. Now, that’s an interesting question. Have you ever read a book simply to use the comparison to it in your cover letter? ^_^
What about the rest of you? Do you use comparisons at all? Only if a particular agent asks? My very favorite query letter request was from an agent who wanted to know which author my story was like and also how it was different. I think she’s who I wrote the Pratchett/de Lint match-up for. Dark urban fantasy meets humor, the difference being more of an emphasis on a romantic subplot. See? That still only makes sense to me.