There are many different, accepted versions of Christianity, all of which choose to interpret Christianity in different ways. Protestants, Methodists, etc... A Christo-Pagan would just be someone who interprets Christianity outside of the "accepted" norms.
I find no fault with that, and think it is probably much healthier than following a religion dogmatically solely because it was how you were raised or because you feel pressure to do so. If those other methods work for you, awesome. If they don't and you choose to make your own Christiany-Pagan tradition, good for you too!