After bolting and unbolting the 12 bolts on my jacks every weekend for the past few months, I built this set of plates and shoulder screws to make life easier. The plates are made from 3/8" x 2-1/2" 6061 aluminum from Mcmaster Carr. You'll need a six foot long section to make four plates, with enough left over for one extra in case you need it. The s/s shoulder screws are part number 90298A705. The shoulder screws will need modification on the lathe. (see attached drawing). The s/s nylon locknuts used to retain the shoulder screws are Mcmaster part 90101A243. I can't verify that this design will exactly fit all other applications, so I suggest that you make and fit a paper template first to see if you need to modify any part of the design.
Disclaimer : My camper is 4WC Fleet shell, so it is fairly lightweight compared to many others out there. This system may not work for everyone, and it is important that you determine the suitability of this design for your own specific purpose before proceeding.
When I went to post this and did a search, I noticed that someone else had a very similar idea. At least for me, this system feels pretty solid and definitely saves a lot of time and knuckles. I realize that not everyone out there has a mill and a lathe in their garage, but you might find a local shop to help you out on this..