I want to do Comparative/Historical Linguistics in Semitics. I want to focus on ancient/classical languages (Ancient Hebrew, Ge'ez, Akkadian, Ugaritic, Classical Arabic, etc.) but many of the classes I've taken have focused on the language's development from the perspective of orthography, not sound. Maybe that is just the nature of undergrad courses though where they don't expect students to know too much. Maybe I'll start looking into doing a NELC degree and collaborate with Linguistics staff as you suggest. I didn't consider the possibility of overlap between multiple departments.
In that case what are some of the better Comparative/Historical Linguistics programs? I have been able to find lists of schools that have good Semitic language programs, but many top Linguistics programs I've seen seem to be more science-leaning than history-leaning.