Now that record labels are barely doing any artist development, it’s evidently up to homeschooling families with musically talented kids to pick up the slack. Remember the now-defunct bluegrass brood Cherryholmes, who seemed to come out of nowhere with its proficient tween pickers? SHEL is upping the ante considerably. These four sisters — all in their late teens and early 20s — started out as their dad’s backing band in Fort Collins, Colo., but wound up stealing the show. They’re no string band, not with their keyboards and drums, and it’d be a stretch to call them a rock outfit considering how often lyrical violin and mandolin take the lead in their music. They’re their own thing. The sisters are working a steampunk look — stovepipe hats and all — and it suits them a whole lot better than it did Sugarland. Their self-titled full-length debut, co-produced by Brent Maher, has an unbounded, fantastical quality to it; here a sweeping, baroque passage, there a tight folk-pop hook, a jaunty vaudevillian cadence, a storybook lyric. You get the sense their parents might’ve mixed some Kate Bush in with the lullabies when they were babies, which is sort of brilliant.