Reducing length of stems of beamed notes after \stopStaff

[Nate Whetsell]

I’m trying to put some beamed notes (no staff lines, time signature, or 
anything else) in a \markup block. To do this, I’m using a Staff with several 
engravers \remove’d, using \stopStaff to eliminate staff lines, and then 
setting Stem.details.beamed-lengths to reduce the length of stems. However, 
setting Stem.details.beamed-lengths seems to have no effect after \stopStaff, 
so the stems are too tall. Is there some other way to get short beamed notes in 
a \markup block?

Here is an example showing what I’ve tried:

\markup { \justify {
  Lorem ipsum pqpqpq dolor sit amet, consectetur adipiscing elit, sed do eiusmod
  tempor incididunt ut labore et dolore.
  \score {
    % Normal Staff with \stopStaff (stems too tall)
    \new Staff \with {
      \remove "Bar_engraver"
      \remove "Clef_engraver"
      \remove "Time_signature_engraver"
      \magnifyStaff #(magstep -3)
    } {
      \stopStaff
      \override Stem.details.beamed-lengths = #'(3)
      \relative { \time 6/8 \stemUp b'8 8 8 }
    }
    \layout { ragged-right=##t indent=0 }
  }
  \score {
    % RhythmicStaff with \stopStaff (stems too tall)
    \new RhythmicStaff \with {
      \remove "Bar_engraver"
      \remove "Clef_engraver"
      \remove "Time_signature_engraver"
      \magnifyStaff #(magstep -3)
    } {
      \stopStaff
      \override Stem.details.beamed-lengths = #'(3)
      \relative { \time 6/8 \stemUp b'8 8 8 }
    }
    \layout { ragged-right=##t indent=0 }
  }
  \score {
    % Normal Staff *without* \stopStaff (stems shorter, but staff lines shown)
    \new Staff \with {
      \remove "Bar_engraver"
      \remove "Clef_engraver"
      \remove "Time_signature_engraver"
      \magnifyStaff #(magstep -3)
    } {
      \override Stem.details.beamed-lengths = #'(3)
      \relative { \time 6/8 \stemUp b'8 8 8 }
    }
    \layout { ragged-right=##t indent=0 }
  }
} }