Here’s a nerd fantasy for you: Tortoise covering Boards of Canada’s “Roygbiv” with Quincy Jones producing. Yeah, it’s totally unrealistic, perhaps even a slight bit musically incongruous, but I don’t give a fuck. I think that would be sick. It is just a dream after all. Now, I couldn’t in good conscience say that Minneapolis duo Keston and Westdal are in that orbit just yet,…