if it is 24p and 60p maybe 30p is nothing new. stuff like this is released even to day.
VFR encode is clearly do able.
it did this as a test about 10 years ago with a 24p 30p mix source which is pretty easily in comparison because a deinterlancer wasn't needed.
not sure if it was
http://www.avisynth.nl/index.php/ExactDedup or just dedup but the trick was 120 HZ and by simply manually multiplying every scene and running the filter over it with a zero tolerance.