I've seen a few diaries and press articles about Riggs Bank. And Moore's film F9-11 also mentions it. Today's New York Times has the most informative article that I have read so far.
Riggs seems to cater to some very high class (read filthy rich) clients. Saudis can trust them for discretion. No background checks necessary. Dictators are not discriminated against. And Riggs is very service oriented... will deliver the cash in suitcases for its preferred customers.
I have not been able to find a Board of Directors List on Riggs site. They have just been sold to PNC Financial.
Here is the NYT link
http://www.nytimes.com/2004/07/19/business/19BANK.final.html
If anyone has found the Board of Directors List, let me know the link.