I found this while browsing this french website, and found it quite interesting so I tought maybe people here would be interested in seeing it too.
Famous mangakas and the famous assistants who worked under them. Some relations are pretty well known, but others might surprise you:
http://www.manga-news.com/public/News%20jap/decembre2011/Assistant-maitre.htm
The best part is at the end:
TEZUKA Osamu (Black Jack): TERASAWA Buichi (Cobra), MATSUMOTO Leiji (Albator)
Looks like godlike mangakas have godlike assistants! XD