Here's a tricky one. Please identify donor, the man who created the modified body and the year when it was built for a point
Experts?
Professionals?
BMW 3/20 PS based?
no
German base car at all?
yes
Hanomag 3/16 PS?
yes
Built in 1930?
almost
The Hanomag 3/16 was built from 1929 to 1931. My next guess is 1931.
no, older
1929 then
:) yes
Was the "man who created the modified body" a known coachbuilder or designer, or is it a private one-off?
It is a private one-off. The builder had a Hanomag workshop in Heidelberg at the time. After the 2nd WW he worked for a company in Stuttgart which is known as Alstom today - according to a patent which was filed in 1959 and can be found in Czech language online.
Hope this helps
Ehemann?
no
Friedrich Mappes?
no
Hans Schmidt-Lasky?
wow, this is impressive. Congratulations
Well, I found out that old address books from Heidelberg are online. ;D