Susan,
I found a site that lists German nicknames. I would have inserted a jump in
this response, but my computer doesn't have the updated browser to read the
page (I was able to read a jump off of it to read about nicknames, but didn't
keep the address).
Anyway, check this site out. It's very helpful:
"German naming traditions" page at
http://www.kalglo.com/kerchner.htm