There is an image of this cultivar on the Hosta Library. From the photo on the HL website, it appears to be a giant size hosta with light green leaves and dark green medial (center) variegation on some, but not all, of the foliage. It is a hybrid of H. 'Big John'. Lavender flowers bloom on tall scapes.  This non-registered cultivar was originated by Virginia and Brian Skaggs of Indiana. 

Xanthippe was an ancient Athenian, the wife of Socrates and mother of their three sons.