Does anyone tow a 5vr with a short pin
If the pivot point is under the trailer, then it is a 'short pin' or 'standard pin'. If the pivot point is out in front of the trailer (mounted on a steel box extending from the trailer), then it is an 'extended pin'.
This makes the trailer/truck combination longer, and requires additional bracing due to the large amount of torque applied to the trailer. So why bother? Well, putting the pin out in front of the trailer gives you more room between the truck and the trailer in tight turns. This may allow you to have a hitch mounted storage box, less trouble towing with the tailgate down, and less chance of 'kissing' the cab towing with a short bed pickup.
In the latter case, most 5ers are 8' or greater wide. If there is less than 4' between the hitch and the cab (ie a short bed), then simple geometry will show you that as you approach a 90 degree turn, the trailer and the truck cab will attempt to occupy the same space. This is generally considered a bad situation
Also, short bed, standard cab pickups (those with short wheelbases), are alleged to be less stable towing long trailers than trucks with longer wheelbases (long bed and/or extended cabs).