Have downloaded and converted Alice In Wonderland and Avatar so far. Unfortunately you need to split the films into ten minute pieces which is a bit of a pain in the bum, and Nintendo haven't allowed you to watch them all one after the other so you need to finish the one you've watched and then physically start the next installment. A bit of a pain but not a big deal tbh, you get a gap of a few seconds before you start the next bit.
I've also found a nice bit of software that not only converts between all of the 3D formats in existence but it also converts 2D video into 3D and it does the latter pretty well. Going to convert some classics I think - Zulu, Maltese Falcon, loads of Hitchcock films, African Queen, American Werewolf in London, Rocky Horror Picture Show, Little Shop of Horrors, Star Wars, Blade Runner...the list goes on and on.
The quality isn't the best due to the resolution of the screen but definitely watchable.