Bulbophyllum praetervisum alba
5" pot blooming size plant available for sale.
Selling the whole pot with 6 leaves for $350, also can sell cutting of the front 3 leaves for $200. 
Only one plant available. 

This alba form of Bulbophyllum praetervisum is extremely rare and difficult to come by. The flowers are pure white in colour, around 5 cm in size. This species can bloom easily in local weather. This whole plant is grown from a cutting, the flower images are from the parent plant. 

Bulbophyllum praetervisum alba