Well, the Prince catalog is a bear to download and navigate. I did find some info regarding high torque, low RPM motors. They are expensive.
I asked the folks at Power Trac for some info regarding converting a PTO tiller to hydraulic. They said that the motor that they use on their tiller costs about $400 bucks. I believe taht it is the same motor that is on their trencher. Add to that the hoses, fittings, couplers, mounts and quick attach plate and that's about $650.00. You come out pretty close to the $900.00 for their tiller, which is probably engineered better than anything that I could put together /w3tcompact/icons/laugh.gif. Now, you could probably find the proper motor for less than that price, but not much.
The guy was pretty blunt. He said that they have engineered these things down to the last penny to be priced competetively with all of the other implement makers. He said if they do not offer some sort of attachment, it is because they cannot make it for less money than someone else that already offers it.
It appears that I need to do alot of studying on hydraulics and hydraulic theory. So, I will be studying more. May be time to take a hydraulics class at the local community college. This stuff facinates me.
I did find some motors that might be suitable for the shredder/
chipper project that I have in mind. They are about $160.00. It is low on my list until I find a cheap
chipper/shredder with a bad engine. They best one that I found so far is $350.00 (ouch). I can wait on that.