I think most of us have thought "Clutch" noise question again.
From what have said, it sounds like the typical noise from the clutch basket. Mine did not rattle, but made the same sort of noise you describe. Most clutch problems will start to have indicators happening, bike creeps forward with the clutch in, slips under load & so on, Clutches usually have a long life, depending on maintenance & abuse.
It may just be in need of an oil change & then its a good time to see if there is any clutch debris suspended in the oil (fibrous material).
I know that when I 1st noticed the clutch noise (& thought "what the f**k is that!) I zeroed in on it until I found out it was normal. Then I concentrated more on getting rid of all the fairing rattles & buzzes (never quite succeeded).