dbusmenu provides a facility for global menus, it's developed by Canonical for Ubuntu but freely available for other OS's. Gtk and Qt support it, but LibreOffice will need an additional patch to do so. A quick review of LibreOffice menus suggests it doesn't use anything that is not already provided by dbusmenu, it should simply be a matter of connecting the dots.
Am filing this bug here to facilitate coordination of a fix, as the issue has been reported in the Ubuntu bugtracker.
Mark: Thank you for the report!
Marking it as 'EasyHack' [though it is going to be an 'Advanced Hack' I am afraid ;-)] to be accessible from
Work has begun on launchpad by http://launchpad.net/~alberto.ruiz to achieve this.
See Bug 664731: https://bugs.launchpad.net/bugs/664731
And bzr Branch: https://code.launchpad.net/~lo-menubar-team/lo-menubar/trunk
initial import of lomenubar with:
Alberto: Should I reassign to myself?
Deteted "Easyhack" from summary
Rebased and merged to master at
Migrating Whiteboard tags to Keywords: (EasyHack TopicUi)