May or may not fit your exact requirements, but Freestyle's APHS, which is primarily designed as a graphic arts film, may work. Abundant in various sizes, and is very inexpensive. Development under a red safelight is also built in. There are many posts here about how to process APHS in different developers for different applications, including in-camera shooting. My estimated EI for APHS in bright daylight is about ISO 4 or thereabouts.
I have shot a lot of this stuff. I shoot it at iso 6 and develop it in very dilute (1:150) rodinal for about 7 minutes ( by inspection) with very minimal agitation. There is a shot on my gallery called roadside lake where I have used Freestyle's ortho lith film. I get good tonal gradation with the very dilute rodinal.