This will be a tough one to get for sure.
Full details on The Alaska DMV Iditarod Finisher plate page. Also covered by The Juneau Empire article about Alaskan Iditarod Finisher plates.
Some prototypes that included the Iditarod crest (which didn't make it to the final design) have also been floating around:
Trivia item: That's Alaska collector Fred Agree's dog, Blackie.