i just tried to merge virutlabox-bin on a clean stage3 set up hp DL380 (x86). i turned out, that starting virtualbox is not possible. i was getting a segfault. after investigating a little, i saw (somewhere in a gdb backtrace), that something with "font" caused the crash (don't recall the exact function name, and fixed it now...). looking at the deps of virtualbox-ose i (for testing) added deps to qt-core and qt-gui to virtualbox-bin. merging these fixed the issue. i suspect it has something to do with libXfont or something like that, since that is drawn into the depgraph by qt.
There's a *lot* of old VirtualBox bugs. Is this still extant?
Should be fixed for quite a while now.