I would note that "not a lot of flavor" does not mean "no" flavor. If you use too much (more than just a couple %), you're still going to get a roasty character. It won't be anything as pronounced as using black patent or roasted barley, but still noticeable. And even at just a couple percent, a very discerning palate may still pick it up. Now, whether that fits with what you're going for I don't know, but I think a "Blueberry Dunkelweizen" sounds interesting and kind of fits what you're going for (not sure I'm sold on the idea myself, but I'm also not wild about blueberries).
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Secondary: Sour Stout, Wild Bitter
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