Hi guys, since I love to see a DP with twin princesses, here are my list of possible movies that Disney might want to make.

1) The Prince and the Pauper

I know that Disney had made this starring Mickey Mouse, if there was a Princess version of it. It would be a good idea, the story setting will set in either South Korea or Japan.
The story will be 100% faithful towards its original story by Mark Twain.

2) The Man in the Iron Mask

I love this story very much, since watching the 1998 version with Leonardo Di Caprio in it. They will base it on the 1998 version, with the exception that the evil twin redeems himself in the end. Making the first twin princesses to become 2 queens and will rule the country with love and peace, making them the 2 beloved Queens.

Conclusion

Since I only have 2 suggestions as listed, if there are anymore suggestions. Please feel free to add more in the comments.