Sweet potatoes I can get, or the next closest thing to a sweet potato, the kumara.Which is basically a sweet potato. It comes in purple, orange and red (white inside).
Black Bean and Sweet Potato Burritos is the recipe, over at Mel's Kitchen Cafe. Just substitute Kumara for the Sweet Potato, coriander for cumin, capsicum for bell pepper (all different names for the same thing) and go easy on those "mild" chiles.
Good luck with the chipotle chile powder. I brought mine in my suitcase... I used Colby and Tasty cheese for the sharp and jack, and we served ours over rice instead of in a tortilla, but either way, it's fabulous. Go make some of this now. You won't be sorry.