Halo
H. 'Halo'
Leaf margins get brighter, turning gold in summer, yet to be able to capture some good images, which show the variegation.

Alternative: H. 'Unforgettable'
Plant Size
  Medium: 13" x 16"  
Leaf
  8" x 4"; chartreuse, yellow margins - margins lutescent  
Flower
  Lavender  
Parentage
  H. 'Flamboyant' x H. 'Estelle Aden'  
Images to follow
In the meantime check out the Hosta Library