Thanks for the responses--those radiators are exactly what I was looking for. Odd that I never turned them up in a Google search. I'll have to figure out how much cooling I need (although I didn't see any heat dissipation specs listed), but at least I know that it can be done so I'll move on to other hurdles.
maxSaleen, I'm interested to hear you ideas on custom hdd cooling. So far I'd just been looking at
this and similar typed solutions. The Koolance looked nice because it allows you to sandwich two drives together so I'd only need 4 instead of 8.
And finally, I would love to hear any thoughts as to how to approach cooling the PS. All of the passive supplies I've seen don't look like they would cut it and all seem to need movement of air in the case via fans, which I won't have. I realize that I'm taking on a large project which will be time (and money) consuming, but I'm doing this really because it looks fun. There are obviously far easier ways of slapping together a RAID-5 system--I could stick in 10 fans and put the whole thing in the basement for a total silence solution. But that wouldn't be fun. I'm willing to take on whatever is required, it will just take me longer because I'm new at this.
The Pentium M is a good idea that I hadn't considered. Your talk of custom hdd cooling got me thinking of possible custom CPU cooling. I have a old 700mhz (slot 1) and an even older dual 450mhz (both Dell's) sitting around which probably run pretty cool compared to modern processors, but would need some creative cooling ideas. Maybe the Pentium M is even cooler running though? I have no idea, I'll look into it.