I did a quick search of the 1850 census with no luck, just as you said. I think I'd try to find a death notice for him and see if that might give you any further info. If the German Near I found buried in KS is your German, then I'd check to see if there is a death record. (BTW, German and Sarah are buried next to each other according to a listing of the burials for this cemetery on the Sedgwick Co, KSGenWeb site.) 1904 might be a little early but it's worth a shot. Either of these might give you some info about his parents. A death notice for Sarah might give you some info about German you might not have, too, but that might be more of a long shot.
I'd also check published histories or biographies of the known places he lived. You might get lucky and find some small piece of info to at least point you to more resources to check.