I am also a descendent of Richard Nelson Allcock through his some James and Polly Housman and their son William Oliver Allcock.
If you'd like to communicate directly, please do.I work for the Louisa County Historical Society and do lots of genealogy work with the VA records.I'm just coming back to my initial research on this line of my family.I found lots of records in Jones Co. for Richard Nelson and the Murpheys there...suspect they all came to KY about the same time just before 1800.
There is another Richard Allcock in Caroline Co., Va (the one I believe another person who has posted here mentions. (Not the same as Richard N. who is checking tobacco weights, etc. and seems has some political connection with George Rogers Clark in the Carolina Co. records. Not sure if they are distantly related to same branch as ours)I have some Carolina Co. and Spotsylvania Co. history records in the office and would be glad to join you both in your search by looking up records here.There is also some really great stuff online from the Library of Virginia, thinking of the early land grants.
Hope this helps to verify that the two Richards are different men, as I see if so far.Let me know if I can help.