Farmall Cub

Has anyone ever thought of putting a Howard reducer on a cub cadet?

I think most cadets are more suited toward using the same speed reducer as used with the numbered series.

The numbered series uses a larger creeper tranny than the cadets do. I'm wondering if the Howard unit would be stronger?

You would have an awesome combination of different speeds using the Howard speed reducer, a set of final drives, the orginal gear reduction on the cadet tranny with the creeper on the input shaft. Then you need some tires that bite to have traction.
Then you can remove the orginal gear reduction and creeper on the input shaft and try the 154 creeper.