Well, the catalog for Liquimoly, the Synthoil people, is here:
http://www.liquimoly.de/web/lmhomeen.nsf/pages/index_produkte
I do not link to oil dealers, but if you look at their web site you can find a link to 3 US resellers.
If I recall, Synthoil 100 was a 15W50 product back in the early...