I think it depends how big it must be to consider "large", but there are tons of California ex-pats living in the Raleigh-Durham area, still working in tech/bio

I think it depends how big it must be to consider "large", but there are tons of California ex-pats living in the Raleigh-Durham area, still working in tech/biotech/pharma/engineering, often for CA-based companies. Most of them arrived in NC because of CoL reasons, having sold a family home in CA and paid cash for a much nicer one in RTP... then likely a beach house a few years later.