Hi,
I was wondering if anyone knows of a case for the Model B?
@Michael: I too am strongly opposed to hype, because hype runs counter to evaluating items and processes on their objective engineering merits. But I am also strongly opposed to perpetual naysaying, because that too rejects objective engineering judgment. This is as true for Raspberry Pi as it is it is for domestic 3D printing. Resisting hype is great, but don't become a perpetual naysayer either.
There are a zillion extremely good applications for RepRap-style 3D printing, and the main reason why it is powerful and important is simply that it places you in control of your own life as far as small plastic pieces go. With a 3D printer at home, you are no longer at the mercy of commercial (plastics) manufacturing like the entire rest of humanity is. The fact that you can make whatever YOU want is extremely empowering, and not having to use a commercial outfit like Shapeways is also faster and cheaper.
Of course domestic FDM/FFF has its downsides, lots of them, but all other manufacturing methods have their own disadvantages too, and the objective engineer doesn't reject any method out of hand. Instead, you match their pros/cons against your requirements for the task in hand and choose appropriately.
The most obvious downside of RepRap-style FFF printing is poor quality of surface finish, which is an inherent outcome of extruding molten plastic filament and depositing it in layers to build up your object. At the current level of RepRap technology based on 0.3-0.5mm nozzles and ~0.1mm positioning accuracy, this can never compete on surface finish with the injection molding quality which we have come to expect as "normal" for plastic goods, nor with the better commercial 3D printing technologies. But surface finish is not always important. Indeed, for many structural applications, it has no practical importance whatsoever, so rejecting domestic FFF for that reason is pure naysaying.
Of course, RepRap fanbois reject any criticism violently, just as Raspberry Pi fanbois do, but that goes with the territory of being a fanboi, all objective assessment is strictly forbidden. No good engineer is a fanboi, nor a perpetual detractor.
I'm building a RepRap-technology 3D printer, a Shapercube -- http://www.flickr.com/photos/morgaines/sets/72157627604533547/ -- but I'm not a fanboi, nor fangrrl. 
I'm fully aware of FFF's many downsides and often discuss them in the RepRap community, and those discussions are not always welcome when the fanbois are out in force. But I also know that when used appropriately, the technology is immensely effective, one of the most important developments in enthusiast manufacturing capability in recent decades.
The doors opened by its (relatively) low cost are as big as those opened by the $25-$35 Rpi, or probably more so. After all, you can buy a good commercial PC for 10 times the price of an Rpi, but you certainly cannot buy a commercial non-FFF plastics manufacturing machine for 10 times the cost of the cheapest RepRap. A 100 times the cost barely gets you into the right territory, so RepRap truly is revolutionary.
On the specific topic of cases for Raspberry Pi, RepRap-type printers can do the job perfectly well since a high quality surface finish is not an important requirement, or at least not a functional one. The reason why you haven't seen any printed examples yet is because nobody with a RepRap has received an Rpi board yet, and the Rpi documentation is too poor to support creating a well-fitting 3D case model from pure specs. The board's connectors are all over the place after all.
Once Rpi is everywhere that situation will change, and I expect that Thingiverse will have so many case designs for reprappers to print that the only "problem" will be excess choice.
Morgaine.
Not to mention that sometimes people do things a certain way simply because it's fun, for them. I once sand cast a wah wah pedal body, not because I had a requirement for a pedal that a herd of elephant rock musicians could use, but simply because I wanted to sand cast something and that was a fun idea. It's now undoubtedly the most robust wah wah pedal on the planet. 
Manufacturing methods are never good or bad in themselves. They are merely appropriate or not appropriate, which depends on your requirements for the end product and your requirements for the manufacturing process, which can even include fun.
Morgaine.
