With the work that I'm doing on tracking down the lives of the Alpha Phi Omega founders, I just thank my lucky stars that I at least have something for all of the founders that I have death dates to within a month (Social Security Death Index just gives month and year) (I'm also getting a lot of other information)
OTOH, for Phi Beta Sigma, one of the three founders is referred to as the "Lost Founder", Charles I Brown for which Phi Beta Sigma isn't even sure where or when (or arguably *if*) he has died. No contact with anyone involved in Phi Beta Sigma was made after 1924 (10 years after graduation)
For Kappa Alpha Psi however, two years ago after a great deal of research on the part of one of the brothers, they identified the unmarked grave of one of their founders and have arranged for a stone to be put in the spot
http://www.rrstar.com/article/20120525/News/305259876
Are there any other fraternity or sorority founders out there that are lost? (i.e. the fraternity only knows they are dead because no one born before 1876 is still alive on the planet) or otherwise completely fell out of communication with the national fraternity/sorority and the other founders?