It is possible to create a new workspace but it essentially just adds a new set of toolbar panels for the existing 3D model. Drawing is also unique from all other workspaces because it's also it's own document. CAM has it's own set of data but also relies on the 3D model. A workspace that you create through the API today would be similar to the Patch workspace in that the set of commands change but the data you're working on remains the same. We have plans to support more in the future to be able to do something like CAM which also has it's own browser. Remember that you're also limited by what Fusion and the API supports as far as what you can draw graphically.