I had read your post about Elihue & James Miller. My relative was William C. Miller born 1817 in Tennessee. I think there is a possibility that James Miller (they lived in very close proximity to Elvira Sewell/Seawell family who William C. Miller married in 1841) may be William's father. On the 1840 census of James the ages would fit for both Elihue ( free white male15 through 19) and for William(free white males 20 through 29). Since I have been unable to find James after 1840 it is likely that he died after that as he was 70 to 70 years of age.
Has there been any Y-DNA testing on the Elihue Miller family that you know of? DNA tests have been done on two male descendants of William C. Miller so this would be a good indication if there is a match there.