Donaudampfschifffahrtsgesellschaft used to be famous for a while as the longest, but it's only 8 syllables as well. Do not know the current status. Of course you can just create longer words, but they are then not 'official' (as far as that exists).

I will create one for you:

Schwerbehindertenvertretungsfachkraftassistent/in.

13 syllables or 14 for the female version. Would be the assistant to a person that works in a council for people with disabilities. Probably wouldn't be named like this, since we wouldn't go that far, but it's possible in principle.