: Silver hair was relatively rare among the Sindar. Only Thingol's family seems to have had it (even Cirdan was one of Thingol's relatives).

: Blond hair is attested among the Sindar, believe it or not. Thranduil, at least, is described as having golden hair in THE HOBBIT. And many people have wondered who/what that golden-haired elf was in "Lothlorien" who helped the Fellowship cross the stream in the forest.

I hadn't realised Thranduil was described as blond. Then again his son Legolas is dark, as was the doyen of Sindarin beauty Luthien. I can't help feeling that, as Tolkien based Luthien's colouring on that of his wife, he would have disapproved of her people being summarily "bleached." In The Silmarillion the impression given is that the only blond Elves were the Vanyar or those with Vanyar ancestry. Another point is - have the MERP people any basis for making Silvan Elves red-haired?

: As for the Beornings, I guess that since they were Northmen the MERP people decided it would be okay to infer some blonds among them. I don't actually object to the idea myself, as the history of the Northmen is quite convoluted. I infer (without any real textual evidence that I can think of) that the Beornings represented a strong Beorian strain among the peoples of the Vales of Anduin. THE PEOPLES OF MIDDLE-EARTH says that most of the Edain of Eriador were Beorians and most of the Edain of Wilderland were Marachians. Nonetheless, even in Beleriand there were golden-haired people among the Beorians and dark-haired people among the Marachians.

A mixture would be fine, but to state that all Beornings must be blond in the face of the only evidence available is nothing short of perverse. There is also the shape changing aspect to consider - a large dark hairy man is somewhat suggestive of a bear, but is the same true of a blond man? After all there are Black Bears and Brown Bears but not Golden Bears - outside the realms of children's toys.