i think you could make this with tunisian. when it gets the the split, you could keep working half the stitches until both halves are long enough and then start stitching across the entire piece again at the other end.
Poncho stricken: Schnittvorlage
paid pattern Ravelry: Azel Pullover pattern by Heidi May. Sweater for a girl
Ravelry: Grey wrap, sleeveless jacket pattern by Laura Dovile