@RRK: Cycling isn't a failure mechanism of SBMV lamps. It happens in low wattage SBMV lamps, when they are burning horizontally. Because of this, SBMV lamps shouldn't be burned horizontally but only vertically.
There were some SBMV that used a halogen lamp in series with the arctube, those will still go out if the filament breaks, but the filament in those won't break if the outer is broken like on a standard SBMV though.
SBMV lamps with halogen lamps, will also fail when the filament in the halogen lamp break, but not if the outerbulb breaks, as the filament is protected from oxidization by the halogen capsule.