I was doing aerial surveying for awhile and they do make the aerial film in 125' rolls as well. compared to standard film it's relatively inexpensive but is quite a bit thinner than standard film so I'd be concerned that in ULF sizes the film wouldn't lay flat enough. I'm also not sure how you'd develop it as the emulsion is made for special aerial developer.
I certainly miss the days when I could just chop up whatever size film I wanted and not worry about the cost sitting in a little plane for 600 hours a year was definitely not worth it though.
If you found a way around getting the film developed I would be willing to be you could call any aerial surveying company and they'd have short bits of film laying around. We would always throw away anything under 30'.
Just an idea