Hi, I suspect without a little more info like date of birth, year immigrated etc, you are looking for a needle in a haystack. I called my dad whose mother was from Megalopoli and where we still have a small property. He was born in Tripolis and lived for a time in Thoknia, a small village outside of Megalopolis. Sometimes names can be associated with a specific village, but he didn't have any recollection of a particular village. I also took a look through a book I have called "Arcadia: A Cultural History" there are lists of the soldiers who fought in the war of Independence as well as lists of those who died during the Second World War. Arcadia is the province in which Megalopolis is located.
On July 19. 1944 a Athanasios Pan. Machairas from the village of Manthyrea (58 kms from Megalopolis) was executed in the stream of Aghios Nikolaos in Tripolis. I did not see anyone else with the same name.
Sometimes the marriage, birth certificates of children or death certificates in North American actually list the villages where people came from, of course depending on the State or Province and the period of the record.
I have been in the Records office in Tripolis, because that is where our family's births are registered (you have a family "seat" somewhere where the family members have been historically registered) and I was surprised that they could find anything, as the filing system was piles of papers everywhere.
Facebook is another place to look as there is a group Hellenic Genealogy Geek where quite of few members have extensive knowledge. One lady is translating all the census records from the 19th century: http://hellenicgenealogygeek.blogspot.ca/2014/04/village-of-...
You might be lucky and find your village has been translated.