Dunno if things have changed since I was flying out of RDU a few years ago, but then some of the Pt 91 operators included:
General Parts/Carquest (Hawker/Beechjets)
Progress Energy (Citation I think)
SAS (BBJ/Citation X/Beechjet...tough department to get into I hear)
Golden Corral
Martin Marrieta Materials (Citation XL)
Bayer (LR55 I think)
State of NC (Citation/BE200/C441)