If you don't mind me chiming in.....
I think even with APO, we've only recently begun doing a pretty good job at tracking our notable members. Thanks to Brothers such as our very own naraht of GC, we now have a thorough list of "famous" members.
When doing this research (because I will bet my last nickel that one of you is going to do it
) it's important not really to look for who is "famous" but who is achieving in their careers and personal lives.
Your national org should have membership rosters, and they should allow chapter presidents at the very least the opportunity to have these alumnae rosters. In APO, we allowed one free print-out per chapter per year.
Get the roster....and google your behinds off! You may be surprised at which of your sisters is now a CEO, local politician, artist, or more.
So it's not so much about finding an already famous member.....celebrate the ones that are achieving and make them famous TO YOU!
By the way.....not to toot my own horn, but I did a similar project for my Alpha Phi Alpha chapter in 2003, because I was tired of people saying certain people were Alphas when they were not (Tim Reid), and keeping the same Brothers on a list (the guys from Shai) while not including people that are more famous (E. Lynn Harris) or more "prominent" (Todd Duncan, the original "Porgy").
The result of my research is here:
http://alpha.mulambda.org/prominent.html
Here is my standard of proof for determining if the man was REALLY an Alpha:
1) Is their name on the National Website?
2) Is their name in the history book or other OFFICIAL publications? (I found out Jamaican Prime Minister Norman Manley was an Alpha just by reading my book!)
3) When I email the national office, do they have a record of initiation? (Just because they don't doesn't always mean they aren't a member, but it helps.)
4) When I email my regions, is there anyone who can vouch for the Brother, including saying they were at their initiation or they've gripped them in the past? (This is how and why I claim disco singer Hamilton Bohannon as a Brother)
5) Does this person's OFFICIAL biography mention Alpha? (That's how I learned Christopher Darden is an Alpha)
Good luck, Service Sisters!