Position a rack in the center of the oven and preheat the oven to 325°F. Spray a 9- to 10-inch Bundt cake pan with non-aerosol nonstick cooking spray.
Whisk the flour, baking powder, baking soda, and salt in a large bowl to blend. Using a handheld electric mixer, beat the maple syrup, oil, vinegar, and 1½ cups of the soy milk in a large bowl to blend. Add the flour mixture and mix just until blended.
Transfer half of the batter to a second bowl. To the first bowl of batter, mix in 1 tablespoon of the vanilla. To the second bowl of batter, mix in the cocoa powder, coffee powder, the remaining ¼ cup soy milk, and the remaining ½ teaspoon vanilla.
Pour the chocolate batter into the prepared pan, then pour in the vanilla batter. Do not worry about mixing the 2 batters together to create a marble effect; as the cake bakes, the batters will blend together on their own to create a pretty design. Bake until a toothpick inserted near the center comes out with some crumbs attached, about 50 minutes.
Let the cake cool in the pan on a rack for 30 minutes, then invert the cake onto the rack and let cool completely. At this point, the cake can be made 1 day ahead and stored airtight at room temperature.
For the glaze, stir the chocolate chips in a medium bowl set over a saucepan of simmering water until the chocolate melts completely. Remove the bowl from over the saucepan.
Stir in the maple syrup and rice milk. Drizzle the glaze over the cake and let stand until the glaze is set. The glaze looks best the day it is made, so plan to serve the cake the same day you glaze it.