Build master~2011-11-27_23.05.31_LibO-Dev_OOO350m1_Win_x86_install-arc_en-US.tar.gz has no user interface in Writer, Calc, DRAW, ... .
Only the empty Menu bar and 2 empty toolbars are visible.
This problem occasional is visible in later builds in a less extreme shape, for example that the menu bar of the start center is empty or other elements of the UI are empty
libreoffice-3-5~2012-01-07_22.47.04_LibO-Dev_3.5.0beta2_Win_x86_install-arc_en-US.tar now shows empty toolbars and empty menu bars anywhere
The MinGW port is not maintained any more.