Need a low rpm gearbox/gearmoter/transmission, where to scrounge?

I need to find a way to gear down a 1/4 to 1/2 hp electrical motor (1750rpm) to something in the neighborhood of 120 rpm.  I can certainly use a v belt and pulleys to make smaller adjustments to get it perfect from there.  This would be running for an hour or two at a time.  

This will be driving a 1" shaft and I can work with nearly any orientation to get it to work.

I don't want to buy a new gearmotor or gearbox even though that would certainly work.  I'm hoping to scrounge something from another application.  So far I've thought of using an old lawn tractor transmission but I can't seem to find any handy.  I don't think bike sprockets could handle the load.

I think a cement mixer would be about the right size/speed so I'm on the hunt for a rusted out one with a good gearbox on it.  No luck yet.

Any other common types of equipment I could get a 15:1 or even 10:1 gear reduction off of?

How about a steering box? I think the ratios might be about right....

What are your torque requirements on the load end? Can this be driven directly using an e-bike/scooter/mobility-chair speed controller?

ATV/Snowmobile CVT might work?

Thanks team!  I passed those ideas along to my partner in crime (who's also got car mechanic experience).  I wonder if a steering box can handle continuous operation...  He'll know.

James, I'm not sure how much torque it will take.  If we're using a 1/4 hp motor and hopefully not bogging it down too hard, at a 15:1 reduction, that probably would generate a torque of some amount that I can't calculate at the moment :)

Update: He likes the steering box idea!  I looked for one randomly on an aftermarket racing site and it was pretty close to 15:1.  Off to the junkyard he goes :)

This is a cool thread. Making popcorn and watching.

Just got a text from him that he thinks one of the gears isn't complete and won't go around all the way.  Not sure if it's just the one he has or if they're all that way.....

Treadmill motors are over 1/4 hp and they come with a speed controller.
Also an automatic shutdown you can clip to your belt,
so it shuts off if you fall while using your machine.

They come with a flywheel to store energy.
They don't like real low RPMs but could probably be run directly off 12volts and run slow.

A worm drive unit is a style that would work. What about a manual car gear box, would there be one in the country?
Some agricultural wrecking yards has unusual bits.
Would a set of chains and sprockets work