I really love the X-Files. And I agree that an accompanying Mulder (perhaps, "mold"-er) shirt would be fantastic.
However, the mouth of this design looks off to me. I understand getting the point across of the character and Gillian's face, but I think you nailed that with the badge and hair alone. I think it looks odd because you have lips and what looks like half a set of teeth.
You're a brilliant artist and I often find myself voting for your designs if and when I see them and this one is no exception, despite the mouth issue. It's a great, original concept and if that part were edited I would wear it in a heartbeat.