I recall you said there might be other options /settings related
to 3d acceleration in virtualbox in the future. If so I think it
might be worth making that element all of its own
<video>
<model type='vbox'>
<3daccel />
</model>
</video>
true, will add a element called <acceleration/> cause there are some features
for 2d acceleration as well, so that will take care of 3d and 2d acceleration
both.
will post a patch soon with the above changes in it.
Regards,
Pritesh