According to Dr. Seuss, the final authority on all matters virtual (in his epic tome, On Beyond Zebra), the letters after "Z" are: Yuzz, Wum, Um, Humpf, Fuddle, Glikk, Nuh, Snee, Quan, Thnad, Spazz, Floob, Zatz, Jogg, Flunn, Itch, Yekk, Vroom, and Hi.
Therefore, expect to see the shiny new yuzz/1 in a showroom near you soon. Mark Llewellyn Visa, Inc.