If you're fine with streaming or downloading it, you can watch the K-On Movie dubbed right now. People who preorder the movie got it early so someone's already uploaded it.
I've already talked about it, but I'll give my thoughts again for those who missed it. It's actually a really good dub. Way better than the show's dub. It's got some minor translation issues but it's still worth watching at least once if you're willing to do so. Especially for Little Kuriboh's role.