Here is some information on Okabe Mataemon (Yoshikata), the head carpenter during the construction of Azuchi Castle. Hide's blog does a good job a photo of Okabe's mansion landmark and a map link.
According the map, Okabe Mataemon's mansion is located near Atsuta Shrine. Having been to Atsuta Shrine many times, I have to admit, I missed this one. If I do return to Japan for the Okehazama festival, you can be sure that I will take a photo of the landmark.
However, there is debate on his death. For example, Okada Masahito's Oda Nobunaga Sogo Jiten, lists Okabe's birth and death as unknown(p. 263). Then you have Jeroen Lamers Japonius Tyrannus who stated that Okabe's death was in 1582(p. 124).
I am tending to go with the Japanese source and not Lamers for now. By the way, I received the 2007 Taiga drama Furin Kazan for Christmas. A damn good drama and highly recommended.
Tenka no tame!