Drive up along side it with the trailer on the outlet side of the chipper. I suppose sometimes things may be a bit tight for that but on a site that can hold enough trees to fill the chip box and more there should be room?
I have seen front mounted hiabs, but they look expensive and they're always on the bigger mogs. How often do you think you would use one? Is your work large commercial or little domestic stuff usually? I think you can get linkage mounted cranes, but just by design I don't suppose they'll lift much at full extension?