I'd say it would result in a waste of time and money and possibly higher case temps. (sorry if that came out a bit harsh) The only purpose I can see the pelt fulfilling is taking heat away from the main waterblock and transferring it to another waterblock inside your case.
In my experience, the simpler the design, the better it will perform. You know why you use Arctic Silver? It's because heat transfer at joined surfaces is terrible. With that layout, you have 2 more thermal surfaces to deal with than with just 1 waterblock.
I would say cool the water outside your case to the temp you want. Whether you do it with a pelt, a radiator, a bong, a fridge, etc, you will end up with better case temps if water cooling is done outside the case.
But, I have been wrong before. Most great innovations are made by someone who has an idea that no one else thinks will work. Keep pumping out ideas!