[Aussie Mike]

I reckon you could do single shock on a Jag rear. The way I'd do it is to put the shock mount in double shear.

I'd make a brace linking the pivot points at each end of the dog bone. The pivot bolt would run through the brace as I'd be reluctant to weld anything to the forged steel end of the dog bone. I'd then have a cross brace welded to the steel tube of the dog bone (welding to the tube would be safe enough). Then from the brace to the shock original shock mount I'd make the double shear mount.

The advantage of this is since the shock mount is in double shear there is little to no twisting loads on the dog bone.
The other big advantage is the braces wold stop the ends of the dog bones pulling forward under hard acceleration and back under hard braking. This along with a set of trailing arms will just about eliminate any change in toe under braking and acceleration.

I've drawn a little picture to show what I mean. I hope it makes sense.