I use a lot of 70mm film, both colour neg and B&W. It's hard to get and limited emulsions, reversal is even more difficult. Colour neg Portra readily available, also Konica 160. B&W neg you have to order a run from the manufacturer, not cheap.
The panorama cameras I use consume a lot film per rotation, I think this is one of the last serious uses for the film as the portrait guys are now using digital.
It's also getting hard to find labs that will process it, I do my own and you may have to do the same.