Get yourself the quite basic Exa or Exa 1a. It yields the ability to substitute the take-up spool for a type 135 cassette.
Though you need a reloadable one as you have to twist its spool.
With the advanced Exacta this might work too, even with standard cassettes, but you should check whether the mouth of the cassettes does not interfere with the sprocket wheel.
Ohhh....lovely design! I used your model as an inspiration, added a handle from a broken Watson bulk loader I had, top box = Zataran's jambalaya, mac'n cheese = bottom box.....Velcro strap to hold the rest together...