Tried to find links to back up anecdotal reports.
Found - Hitler’s Black Victims: by Clarence Lusane on Amazon.
Try the US Holocoaust museum site (www.ushmm.org) follow down the page for web links.
IIRC the Washington Post Book Review section recently reviewed a book about American POWs who survived German concentration Camp.
I also remember from one of Ambrose’s books, I believe, that Jewish soldiers did not list their religion on dog tags.
To add to your list you should also include the Slavs. From what I understand the treatment of US soldiers was better than other nationalities (esp. the Russians). There were instances of summary killings and deportation to concentration camps but I don’t believe it was the norm - not to defend the Germans if you read about the treatment of Poles and Russians.