Funny you should bring up the topic of pumps to run from the PTO. I have been musing on that for a while as I consider which pump would be best for my planned sprayer wagon.
A Cub being 6 volt is not exactly set up to run those 12 volt sprayer pumps, so I was looking for something to run off of my PTO. I found it.
It is called a self-lubricating gear pump. You can find an example of what I mean by going to http://www.princessauto.com
and downloading their latest catalog. Not the sales flyer but the big catalog. It is a PDF file. Once downloaded go to page 93 of the catalog and you will see what I mean.
Now, a platform will have to be fabricated and you must make this a direct drive application or it will wear out very very quickly. You will also have to get a union to fit the PTO shaft and reduce down to the pump drive shaft.
Nice thing about this pump, max rpm is 1800 == gee, I wonder what the max rpm on a Cub is
partsman and I have already figured out most of what I will have to build for the sprayer and this pump is the puppy to use. I hope this helps.
Oh, I imagine you should be able to buy a pump such as this at Harbor Freight as well or a Farm Supply store.