There is an image of this cultivar on the Hosta Library. From the photo on the HL website, it appears to be a large size hosta with dark green leaves and yellow medial (center) variegation. This non-registered cultivar was originated by Jim Schwarz of Jim's Hostas of Iowa (now owned by Uniquely Hostas of Wisconsin) . 

MyHostas database says that this is actually H. 'Grecian Vase'.