i found a site which lists almost 400 "qualified companies" and almost 1000 "qualified individuals", but i'm not sure how complete and updated that list is or how they get their information.
(a few names there i recognize from WebmasterWorld membership.)
a search for "google adwords qualified professional" returns over 50,000 pages on google.
i would believe the true number is closer to 1500 than 50,000.