Welcome to AC, Papajin, and thanks for a great link! Somehow, I had missed that company in my HTPC related surfing.
Yeah, I saw that the other day. Their Heatsink HTPC case is truely awe inspiring, but $1000 for a case!?! 
I configured one and hit roughly $1100 with all of the passive cooling devices added. This is definitely not cheap and much higher than I would like, but it seems inline with other similar cases (solid aluminum construction with fully passive cooling via heatpipes).
I am going to knock off a DIY version of this case when my project list allows for it. I also have a couple ideas for improvements to the design.
You have a less expensive source for (mostly) billet aluminum cases? I'd definitely be interested in learning more about it. I plan on going this route at some point, but there seems to be rather limited availability of passively cooled cases that look like audio components.
FWIW, a great resource on silent computing for anyone thinking of doing audio or HTPCs is silentpcreview.com.
I'll second that recommendation. They are an excellant source of info on quite PCs.
I built a linux file server (just installed Red Hat 9.0 last night actually, it was a breeze). My plan was to have all the noisey HDs elsewhere located, in this case, in the basement.
Good idea. (Wish I had a basement!)
I'm risking a detour off topic here, but why RH9? It was end-of-lifed a year ago this past April, so you can no longer get patches or security updates. In addition, the 2.6 series kernels are definitely higher performing that the 2.4 kernel in RH9. (My home desktop machine has a RH9 partition and a Windows 2000 partition, but I almost always boot into my SuSE Pro 9.3 partition.)
Thanks!