Tungsten arc is a common failure mechanism of these bulbs.
Projection and theatrical lights have much heavier filaments and
so the problem is a lot worse. There's not a whole lot that can
be done about it, and certainly bulb orientation won't have any
effect.
Fuses? This is exactly what fuses are FOR, to remove current to shorts!
Properly designed and sized triac dimmers should survive at least a few
of these incidents, but cheap dimmers are probably designed to only
survive the normal load current. A fuse fast enough to protect the dimmer
will probably cost MORE than the dimmer, but they are available.
Jon