Reducing the length of a broken beam/beamlet/beam fragment?

[Marcus Macauley]

The partial beams that you get with, e.g., a dotted rhythm: Is it possible  
to reduce the length of such beamlets?

I think Lilypond's default minimum length is a bit too long, especially  
for tightly-spaced music, but I haven't been able to find a way to change  
it.

Marcus