Bob Hoskins. Here he is as Odin and then as Badger, from Wind in the Willows.
He's maybe a bit short for a bear, but that's no impediment to an actor of his abilities. He lumbers very well, has a great sense of humour, and does delicious villians.
I could even see him as Bilbo, depending upon how young the director wants to make Bilbo appear (as opposed to how old he is in the book).