Songs with 2 guitar parts & 2 voice parts?

I'm planning to do my senior project with a friend and we would like to perform a song. We're willing to learn whatever instruments that go along with it but preferably either two guitars or a guitar and piano. We were considering doing Winter Song by Sarah Barellis and Ingrid Michaelson but we would also like to explore other options. We're both altos, but both have a good range. Think Tegan and Sarah? Just looking for some ideas(: