I don't think it is meant to be Radagast, but that might explain how that little fluttering moth always gets places ahead of the eagles...those birds can move!!!
I had read something that concluded Bombadil was Iluvatar, but Aule makes more sense this author examines the stories. Funny that the dwarves have had enough interactions with him to call him Forn...but they have no idea he is their creator! This paper was very nicely done. Old Tom always seemed to be lot more than just "a merry fellow"!