I might be wrong, but I think Thor is "Thunderer" rather than 'Thunder'.That's a good idea, something I've been thinking about. It's not uncommon as I've been learning about names, to have an element repeated in the first and last names. So, Thorbjorn Thorsson is not unreasonable or unheard of. In fact, it's pretty common. I like the ring of it too. It translates as "Thor's bear Thor's son" (or "thunder bear thunder's son").