This will become a regular feature, and I will collate the famous ukers on the Famous Ukulele Page accessible from the menu at the top. There is a link on that page that gives you access to all of my editions (now up to edition 13!!)
Neil Armstrong (yes, THE Neil Armstrong)
Loudon Wainwright III
So. there you are - if you know of any others (and have pics) let me know and I will upload them.