I'm running 11-26 and 12-28 that I got for $5 each from catalogue lol.
Here is 9 speed 11-36 Bikeman Shimano HG61 9-Speed 12-36 tooth Cassette for 29er
I wish there was a cassette with a 34 low that was something like 13 19 24 28 31 33 34 It would work great at speed in the big ring, and work good for towing in the low ring. Probably will never happen though without hacking together a bunch of old cassettes. The mfgrs seem to be making things that jump more as you go lower in gears like these 9-36tooth things.