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 heavily corrugated, dark green leaves with yellow streaked variegation.  'Hallie's Comet' is a hybrid of H. 'Sand Pebbles' × H. 'Sieboldiana'. This non-registered cultivar was originated by Rick Goodenough of Massachusetts.