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!
OK, I think I get it. Those rectangles are for the water I/O.
You don't mention whether they're both connected to the same water system or not, which could have an impact on performance (and will have an impact on your cost). There was an article (lost the link ) in which someone tried to use a waterblock-pelt-wanerblock sandwich, but it was a major failure. I don't doubt that somebody will post a link later.
I love innovative, creative and cheap ideas (2/3 isn't bad) but I'm glad that you posted here before you dove in. I highly recommend that you don't do this mod. It might work out acceptably if you used two separate watercooling systems, but the cost would be about twice that of a normal watercooling system, and would give you diminishing returns.
I certainly don't mean to scare you avay from being creative, just from this idea.
overclocker- read the article. I think the problem with his is that the water didn't spend near enough time in the chiller. As you can see in my picture (that IdeaMagnate kindly put up for me), you can see that the inlet/outlets are 1/4", which would restrict the flow in your typical 3/8" system. Internally it has channels that would be a lot like a heatercore, larger diameter channels on the sides and thin (wide?) flat tubes running through the center.
In a chilled system a low flowrate would be ideal