Apparently there is a foundation dedicated to Roscoe Filburn of Wickard v. Filburn fame! This was not around when I did my research a few years ago. As for the fate of the farm:
The Filburn Farm was a part of his grandparents’ farmstead which totaled 640 acres. Most of the land was sold in 1966 for the development of a residential area and the Salem Mall. A street on the land was named Filbrun Lane in his honor. You will notice the spelling of his last name changed; something he did years after losing the Supreme Court case. Roscoe pursed other interests including buying The Beverly Shop in nearby Brookville, Ohio which he managed with his wife, Virginia. They had two children – Mary Lou and Roscoe Jr. (Tommy) – and neither became farmers; however, he continued to farm until his death at age 85 on October 4, 1987.