I've committed support for stretching piano scores to the jneeman branch, but there are still problems. input/regression/beam-
cross-staff-slope.ly is currently broken and the piano staves are positioned (IMO, but I am not a pianist) too close together.
This last one is giving me some problems: I have removed forced-distance and collapsed everything into one VerticalAlignment. So now there is no way to say something like "the staves of a piano staff should be positioned at least 8 units apart". I'd like to do something like \override
PianoStaff.VerticalAxisGroup #'minimum-Y-extent = #'(-4 . 4) but of course it doesn't work because the Staves that are children of PianoStaff have their own overrides. Any ideas for how this override should be done?