Since the 1st of September 2014, incandescent reflectors in all sizes will no longer be made due to the European Union ban on incandescents. The ban requires that the bulbs have at least a life expectancy of 2,000 hours and meet a specific lumen output.
The ban has taken place to try and make the move to more energy efficient lighting. In terms of replacements, lower wattage halogen reflector bulbs offer the same quality of light as the incandescent version. Another energy efficient alternative is an LED version.
For the time being, you can still buy original incandescent reflectors until they are no longer in stock.