Looks like there is a new one-stop site for all your digital movies.
MoviesAnywhere.com will be replacing DisneyMoviesAnywhere.com, and also allows you to link your iTunes, Amazon, and Vudu accounts, so that all your digital movies from these services are visible and streaming from one site.
They have a promo going right now to get you to link accounts. Linking one account will get you free copies of Ghostbusters (2016) and Ice Age. Linking another will get you Big Hero Six, Jason Bourne, and The LEGO Movie.
However, this site just launched, and seems to have some growing pains. They have a banner up right now that VUDU linking is disabled, and I was unable to get Amazon to work either. The error indicated a time out. However, I figure these issues are temporary, and free movies are always a good thing.
Note that the site seems legit. There was a write-up on Ars Technica about it, and more importantly, if you go to DisneyMoviesAnywhere, they have a banner up indicating that site is going away soon, and you should migrate your collections to this new site. Signing up for an account on MoviesAnywhere.com with my DMA e-mail automatically migrated my Disney collection over.