As handy as such a list of Virginia slave traders would be, I know of no such. Try this book:
Frederic Bancroft, Slave Trading in the Old South (1931), especially chapter 5 "Virginia and the Richmond Market."
(Other chapters cover other states and topics)
For SC also look at:
Michael Tadman, Speculators and Slaves (1996), Appendix 4: South Carolina Slave Traders of the 1850s
Google would probably net you some results also.
Are there updates to this listing?