I can see the logic of mounting it as close as possible. It would reduce the effective weight on the 3ph lift system. It would reduce the tendency to resist steering input due to rudder effect. It would keep the overall length as short as possible. It would compensate for the additional length of any quick-hitch or Pat's type interface.
On the other hand, it would increase the driveshaft angle fully lowered and/or fully raised. It would place it closer to the operator and/or potentially interfere with tractor or cab. It might be harder to see where it is as you twist around in the seat to see where you are going.
Given that you can always shorten the driveshaft more but can't lengthen it, I personally would start with it as long as possible and move it in as appropriate depending on how you find things after trying it out.