I doubt you'll find a positive statement -- "we think it came from X" -- because, like any other work of fiction, it doesn't really concern us. As hinted at in the question, Jews do not consider Muhammad to be a prophet. This is for at least two reasons:
The age of prophecy had ended by then. When we next see prophecy we'll be in the time of the moshiach.
Parts of the Quran contradict the torah, and we do not believe one claiming to be a prophet who conflicts with torah. See D'varim 13 (h/t Shokhet).
Whether Muhammad had a dream or delusion that he honestly believed, or he or his followers wrote the book on their own initiative, doesn't affect the outcome. The Rambam believed that the practice of Islam is monotheistic and so not idolatry (avodah zarah), a status he did not grant to Christianity, but that's a far cry from supporting any of what the Quran says about its origins. I have the strong impression that, among traditional rabbinic sources, the Rambam takes the kindest view toward Islam -- so if anybody were going to grant credence to the claims of the Quran I would expect it to be him. But he didn't.