What about something like this with a Clevis clip?
Clevis Pins Type: Standard Pin Diameter 67932764 - MSC
Of course, you can get this and similar at the local HW store.
I use the stack jacks too, but I don't regard them as terribly "easy" to use. They're kind of finicky IMO. They do work, and they are cheap, but I'm looking to permanently install scissor jacks where I currently use stack jacks.
2014 Jay Flight 28 BHBE
2015 RAM 2500 6.4L HEMI, Tradesman 4x4, 3.73
Blue Ox SwayPro (BXW 1503)
Upgraded from an REI internal frame backpack and a Eureka 1/2 dome tent!