I would LOVE to see a movie for Animorphs. Not really based off any specific storyline in the books, just based off the books in general. Kind of like how the original Power Rangers movie didn't have anything to do in the timeline of the series, nor was it based on any specific plotline from the series, or like any of the recent superhero movies aren't based on any specific plots from the comics, just off the general ideas.
With today's effects and larger-budgets, and the rise in Superhero movies, they could easily do a 2 and a half hour long Animorphs movie that caters to both kids and adults alike that could be truly epic.