I ran a milemarker hydro winch for a few years starting in '96. This was on my K5 and I'd had enough influence from my Dad's industrial world experience that the hydro seemed like a good way to go. Except I wanted some speed and mile marker used the power steering pump which as mentioned doesn't make much power. So I mounted a clutched pump on the engine (like someone else mentioned) and ran a spool valve to power the winch. It was pretty amazing, between the spool valve and engine RPM control I could go from 0 to around 50 feet/min smoothly at full line pull and that just doesn't happen at all in the electric world. Most electric winches run about 4 feet/min at full load. It was bulky enough that it didn't make the TTC build on the K5 and for offroad use the electrics we've been using since then will do the job and are way more convenient.
I couldn't get more than about 1700 psi on a single V-belt and I didn't have a good way to put another belt on the pump so I just went to a more powerful motor and slowed it down a little to work with that pressure and still give me about 10-12K pull. I think overall the engine driven pump is WAY more convenient for the use you'd put it to in recreational 'wheeling or even light work use. Being able to vary engine rpm without changing road speed by working around the torque convertor is pretty nice.
