Bryan,
You got me thinking about this setup (my ADD kicked in) and it's intriguing for guys like me with no space for big, permanent tables. I rarely have to transport anything but I do have to knock it down for storage, hence the modular 80/20 cutting/assembly table. The only problem is this take too long to set up unless I am going to be working all day. Your idea would be fast.
Here are a couple thought that jumped to mind:

In that one the 1530 rests on the top of the jawhorse, the clamp grabs the 1515. This idea depends on the height difference between the clamp jaws & the top of the jawhorse being < 3", I am only guessing it would work without some modification. The next one would have the table top cantilevered in both directions, may be a bit shaky but I don't have a jawhorse, not familiar with how sturdy they are:

The best option may be a hybrid, 1530 in the center and at the end, so one side of the top cantilevers and the other rests on the jawhorse. When not in use the table top can be hung on a wall.
This is worth playing with.
RMW