Hopunion has an "aroma wheel" for hops. You can't see all of the flavors at once, but by clicking on various flavor profiles (Citrus, tobacco, fruity, etc), you have access to a decent amount of information on more hop varieties than most people even knew existed.
I'd be wildly interested in anything like OP requests for malt varieties. I've seen some which display diastatic power, but nothing with that plus aroma, taste, color, or common issues (Like pilsner malt being rough on DMS).