I think it will be tricky, or would be rather time consuming. But it is possible. The one thing is that you can do whatever you want with your Spark app. The "dashboard" is pretty easy to customize, but if you want to control the "settings" pages, that is where the tricky-ness will be.
But since you are using a Bootstrap theme, it might be easier than I initially think. Most Bootstrap themes use quite a bit of the base styles, and provide a "theme" css file for its custom styles. It might take a little work to get things playing nicely, but the "settings" area uses Bootstrap.