How common are Non exempt salary jobs

Federal GS jobs are like that, at least for some agencies. Hours are tracked for time and attendance purposes, as well as leave, credit, comp, etc., so you could argue they're "hourly". They publish an hourly rate, primarily for OT or leave without pay purposes.

But certainly not "hourly" as the general public uses that term.

I work for an oil major and we have some jobs like this. We consider them paraprofessional.

It's the middle ground between hourly people and technical professionals.

Our people only need to track and charge the OT hours. Their base rate is covered.