what is it for, primarily?
darkstar,
we have a prentice 120C loader installed on a similar truck to those pics in the link you posted. overall a very similar setup to what you mentioned: dumpbed, loader, single axle truck. i am assuming the single axle part. if we had to buy another loader, we would go with a double rear axle. the weight of some logs is just too great, and a former operator at our company actually put the truck on its side the first week of operation ( a heavy stump with the boom fully extended ). whoops. luckily no damage.
what i wonder is what you are going to be using this dump function for. our outfit has a separate truck for chips, so our loader truck never really has to dump. we will dump our loader once in a great while, but don't be fooled, this is no easy operation. as you see in the photos, you have to put the boom way up in the air (we actually just keep it low and swing it 180 over the truck's cab), hop off the loader and dump it, then, and here's the part you can't see in the photos, raise the outriggers and drive the truck forward with the loader extended and probably on somewhat uneven terrain. do you see the inherent danger in this? i probably don't need to explain it, but a bed that long needs to be emptied by driving it out - the pile behind the truck will just be too big to dump without going forward.
so anyway, i am a big fan of the log trucks with standards instead of solid walls now, since we primarily (90%) just load and unload logs into the truck. you get a loader with low hours and a nice grapple, and you can unload/load lightning fast. however, if you are planning on chipping into it as well as loading into it, i guess you'll need the hard sides and the dump function.
hope i explained myself adequately.
winch