>>1577169they exist
they're called dummy levers or stoker hoods (for tandems) like these Cane Creek ones.
It's not hard to make either. You just clamp a short cable run under the lever clamp to keep them tensioned and stop them rattling around and hacksaw off half the lever and sand/file it smooth
or this:
https://www.youtube.com/watch?v=Fs4QGFJUToc