Disney released postcard-sized lenticulars of the Changing Portraits that morphed as you moved the card back and forth. There have also been some larger sized versions available (over $1000, from what I've seen on Ebay).
A more afforable version can be found either on Ebay or (if we're allowed to plug a website) Haunted Portraits.
Every once and a while there are some really neat HM things on Etsy. Once I saw an exact replica of the "Tomb Sweet Tomb" piece that is hanging in the corridor of doors. You just kind of have to keep your eyes peeled.
I know at one time (if not to this day?) you could print on demand the entire set of the regular stretching room portraits from those kiosks... do they still exist? I remember they were really pricey though even as prints... not even canvas or giclees (sp?).
I haven't been since December of last year, and I didn't look back then.