I have a Pioneer DVR-105/A05 model, and Panasonic had a utility that would let you set the drive operation mode. To two operational modes were 'quiet' and 'performance'. I set mine to quiet and it is fairly quiet (though if you're looking for it, you'll certainly hear it).

I know using the Omega drivers, I had a huge clock speed selection for a 9600xt I was using. I tried clocking it at 150MHz and my graphics related power dissipation went from 34W at stock (500MHz) to 25W. I could have underclocked further but I only went that low for experimental purposes. Its a sha...

Well, it "is" being worked on apparently. No one is hinting any time frame, status, specs or anything.

But just for interests sake here is a prototype that was scrapped:
SS53GR
The name is curious though as it would imply a SiS chipset from Shuttle's naming convetion.

I think if you can, it is best to use a vacuum. This way the dust is caught and you do not have to breath the crap that was just sitting in your computer for eight months.

I would also be nervous about the whole thing slowly melting through the clay as the clay would probably act like a very viscous liquid.

If your case has the ATX style layout where the PSU sucks air across the CPU, you might be able to get away with passive cooling if you install a large enough heatsink. I have seen a few Pentium I, Pentium II era designs with a passive setup.

I wouldn't be surprised if Sapphire has discountinued the 9600 UEs since the Toronto area retailers that I knew used to carry aren't any more.