Somehow last year I missed the part about smileboxing movies.
I made a post about it over at hometheaterforum: http://www.hometheaterforum.com/topic/318892-70mm-film-transfer-to-bluray-using-smilebox-simulated-curved-screen/page-2#entry3895740
I even made a (crappy) video here: https://www.youtube.com/watch?v=j3GpFcn-yXg
It can be easily done in real time using this program: http://www.fly.elise-ng.net/immersivedisplaylite2