I'm intending eventually to write a book tying together all the Quintrells. I believe there was one common ancestor of all living Quintrells and probably of all Quintrell descendants now living. I am not intending to trace all lines down to the present, but will include lines where I know there is genealogical interest. Otherwise, I intend to bring all lines down to 1837, the start of civil registration in the UK.
I don't have a lot on US Quintrells, but it would appear that there were few of them at the 1880 census, and hence earlier. I think the John I mentioned was baptised in Camborne.