I began playing around with this rig a few years ago. I wanted a short rig for pva bag work. I was looking for something a little different to the norm. It had to be supple on the hook end but I wanted to incorporate a stiff boom. Obviously, this would cause trouble using in a solid pva bag.
Playing around with different materials and rigs, I tied a combi-rig consisting of a short 3 inch boom of RigMaroles CamH20. The properties of this perticular hooklink come into their own as you'll see in a bit. The other end, the supple part to hook, was tied with rigmarole's skinful. This was fully stripped of its coating. It creates a lovely supple part that is thin put extremely strong.
The hook was the then on test Hunchbax which is a cross between a curve shank/ long shank hook. Once tied as a combi - rig using the Albright knot, it can then be manipulated into the rig I wanted.
Get a small round baiting needle and the boom section is coiled around this tightly. When you pull the baiting needle out, you are left with a spring like boom section and supple hook section.
The whole rig is about 3 inches or so long. It goes perfectly into a pva bag.
When you catch a fish it works similar to a spring, pulling the hook home better. Once you've played the fish in no one will be any the wiser at what you've done as the boom section pulls out dead straight after the fight. It's then just a case of wrapping the boom around the baiting needle again to get it ready for more action.
Give it a go. I think you may like it where pva bags are being used.