Have a look at these for classic german designs.
These items are door levers not door knobs. “Türdrücker”.
They are selling volume in the US right now, thanks
to the changed legislation concerning the accessibility
of public buildings for handicaped people.
Another good one is here:
http://www.hewi.co.uk/content/uk_en/
70ies Dieter Rams:
Yours mo-i