Hi Andrew,
I'm not sure to understand what you're looking for.
A more precise description or a teeny example would have been helpful.
Anyway, here's something I've done i order to look-like your picture:
\version "2.19.31"
my-tempo = \markup {
%% Left arrow:
\overlay {
\arrow-head #X #LEFT ##f
\override #'(thickness . 1.5)
\draw-line #'(8 . 0)
}
\hspace #0.5
\lower #0.5
%% Note value 1:
\overlay {
\raise #3.5 \beam #0.7 #-.5 #.4
\raise #2.8 \beam #1.0 #-.5 #.4
\override #'(thickness . 1.5)
\draw-line #'(0 . 3.5)
\rotate #10
\translate #'(-0.05 . 0.1)
\musicglyph #"noteheads.s2"
}
\lower #1 "="
\hspace #0.5
\lower #0.5
%% Note value 2:
\overlay {
\raise #3.5 \beam #0.7 #-.5 #.4
\raise #2.8 \beam #1.0 #-.5 #.4
\raise #2.1 \beam #1.3 #-.5 #.4
\override #'(thickness . 1.5)
\draw-line #'(0 . 3.5)
\rotate #10
\translate #'(-0.05 . 0.1)
\musicglyph #"noteheads.s2"
}
\hspace #0.5
%% Right arrow:
\overlay {
\arrow-head #X #RIGHT ##f
\override #'(thickness . 1.5)
\draw-line #'(-8 . 0)
}
}
\relative {
\tweak extra-offset #'(4 . 0)
\tempo \my-tempo
\tuplet 5/4 8 { g'32 g g g g g g g g g } s
}