It might sound like a backhanded compliment, but Downtown Owl feels more like a pilot than a feature film and may yet yield a series. In today’s market, that could work out just fine for directors Hamish Linklater and Lily Rabe, who, after a choppy start, finesse Chuck Klosterman’s digressive 2007 novel into a thoughtful, broad-canvas ensemble piece. T Bone Burnett helps nail things down with an eclectic alt-country score and soundtrack, infused with the music and spirit of Elvis Costello, but it’s Rabe that holds it all together onscreen with a controlled yet still wildly uninhibited performance.