I just found your Juniata Valley Genealogy Forum posting from 2003 and have some information on Leonard. I am hopeful of finding information myself, that would prove Leonard to be my 3rd great grandfather.
I am descended from John D. Cochell through my mother and feel that Leonard was probably his father. Leonard was a resident of Pennsylvania until he died in 1824. John D. was born in Berks County, PA, in 1792. I would look at census index records for Berks County and Miflin County, PA.