They're out there, they're just rare. The Generations versions of this mold (like thundercracker) are much more common than the Classics ones. Cheapest I've seen one go for was $20 in a multi-bot deal.
Contact me if you have for sale:
Transformers: The Ultimate Pop-Up Universe Book
Botcon 2006 Dawn of Futures Past Boxed Set
MP-01 Matrix
POTP Onyx Prime