I've used 70mm film since about 1978. The Hasselblad casettes *ARE* Kodak casettes. Kodak used to sell 70mm 15' pre-loaded casettes. On occasion you can find an expired roll of 15' 70mm film that the seller doesn't realize that the film has a new cassette inside. I have bought a number of them like this just to get the cassette.
I have a Mamiya 6x7 70mm back as well as a couple of Hasselblad A70 backs. You get 70 frames 6x6 with the A70 back. Back in the day when Tri-X was available in 70mm 100' rolls I would load up an A70 back with Tri-X and with my Hasselblad & 80mm lens hit the streets. Never had to change backs!
I have the Alden 70mm bulk loader, a 70mm SS reel and a homemade daylight developing tank that I made out of a daylight print processing tube. Drying the film is a pain! At frame 35 I shoot a blank frame so I can cut the film into 7.5' lengths so that it will hang in my dark room to dry.