I believe they had some in the candy shop on Main Street and then again at Goofy's Candy place at DTD. I remember, because DH and I always joke - he bought some by accident one time. Way too sweet for us.
What a great idea!!!! I have a gazillion WDW popcorn buckets, too! Pop it in the room before you leave for the parks, put in the bucket and go! PERFECT PLAN!
You can get some good stuff from http://www.popcornman.com! The KK from the craft shows/fairs is always better than the store bought or microwaved kind, IMO!