I have used a more robust way of identifying to which assembly a call belongs. Rather than just the namespace, the signed key for the assembly can be accessed through the Context property.
I imagine on the front end that one way a user would want to make a query on the types usage is something like: System.Text.* or System.*.
I have talked with Alex Orso who has pointed out some related work in residual coverage testing.
Furthermore, I have began setting up my testbed. I've been trying to gather various Mono applications in the wild. It is not as straight-forward as it sounds considering how diverse each project configuration is. So any donations for Mono executables would be accepted :)