The John Coleman Cabaniss that spent time in Tuscaloosa, Alabama during the 1830s/40s went to California during the Gold Rush. He first shows up in San Francisco around 1850 and supposedly there is an obituary stating his death around 1857 in San Francisco. Type in J.C. Cabaniss or Cabiness in Google or Yahoo and it should bring up some city tax assessments with him listed.
There is a possibility that this John C. Cabaniss married Catherine Mayfield Cabaniss a widow of Peter Randolph Cabaniss who died in 1834, but so far I have had no luck tying the two together. Peter and John I believe would have been cousins.
Is this John Coleman Cabaniss the same one as your GGGGGrandfather?