I have traced my McConnachy family back to Saddell, Argyllshire. I have a John McConnachy (born in Saddell in c.1805), his father born in Saddell in c.1779 and I think his father was Duncan McConnachy (but not sure).
By the way, I believe the derivation of McConnachy is as follows -
* Mac or Mc means "son of" * Conachie or Connachy is a derivation for Donnachaidh (which is Gaelic for "Children of Duncan").
Therefore McConachie (and therefore I believe McConnachy) means "Son of the Children of Duncan".
I wonder if you have any more info on McConnachy in Saddeell on the surrounding area...