Actually, "Graphic Novel" is the more appropriate term. Independent artists and writers have created stories inspired by the music of Belle & Sebastian. They will be collected in this Trade Paperback (scroll to a little more than half way down the page).
Whether it'll be good or not, I dunno. But I do know it's a cool idea. Nick and I actually had this thought years ago, for our other brother's band. But it was more superhero. With hippies and exploding drum sticks. I kid you not.