Kindle Voyage -
KV
Kindle 2014 -
KTN (Kindle Touch Next or Kindle Touch New or Kindle Touch. Not!

).
K5B (K5 Bourbon, after board name)? To the fullest confusion Amazon names it Kindle 7th Generation on Source Code Notice page.
K7TH?
KTHXBYE
EDIT:

can we have KTHXBYE as a last prefix in select box in this subforum just for fun?