My issue is at the price range of the Cub Cadet your are looking at (roughly $10k), you are in high end commercial ZTR territory which opens up LOTS of doors for ZTR's that should be able to handle anything that cub cadet machine can.....
Off the top of my head:
Scag Turf Tiger
Ferris is2000 or is3000
I think I have read the Turf Tiger will run on hills up to 20-25 degrees? They have a nice and low center of gravity.
Both of the above are 10x the machine of the cub cadet and will last for 2-3000 hours of use.