Showing off what you've got and easy access is worth risking a little dust.
Transparent acrylic PC cases aren't exactly new, but AskTech Co. has at least two acrylic cases that are definitely designed for showing off your workstation's innards. The unimaginatively-named NK-OC350A is less PC case and more a platform for "open-air testing". The motherboard mount (for miniITX, microATX, and ATX motherboards) is slanted towards the viewer, with the drive and power supply mounts situated directly under.
The NK-OC450A on the other hand is designed for more stability, with the motherboard separated from the other components by non-angular shelf. The whole setup is also contained within a steel frame, but it's easy to remove the top cover for maximum exposure.
Both of AskTech's offerings are advertised as testing platforms, so you can bet it appeals to frequent overclockers and hardware reviewers. Not to mention boastful enthusiasts who'd want the best way to showcase their setup on a wildly active computer hardware forum. And at an estimated price of $50, the NK-OC350A won't exactly burn a hole in your pocket.
Unfortunately, AskTech currently only sells in Germany, Japan, Eastern Europe, and Korea (where they're based). The company rep revealed that they were looking for a distributor in the US though, so let's see what happens.