Given that this is put out by a non-profit organization and the Broadcom data sheet is not available, I would be very leery of using RPi in a production scenario. Better to use something like the Beagle Bone from TI where you can be assured of getting the boards you need as well the information to resolve any issues.
RPi may become a victim of its own success in that some of the companies donating the chips to keep the cost down may decide they have donated enough. Also did I mention that Broadcom refuses to release the data sheet?
This is really a very good collection of the possibilities demonstration by Raspberry Pi. To my best of knowledge this will be really a very helpful article for the students and learners for designing projects using the modules. Yup many will be able to participate in further development of the vast possibilities.
Here's another useful RasPi board I've come across, though I haven't tried it myself. Guzunty Pi is an "I/O Extender" board using a Xilinx XC9536XL or XC9572XL CPLD. It's actually sold as a kit, with a 44-pin PLCC socket for the CPLD and through-hole components for easy assembly. You can download various CPLD images for common I/O configurations, or program it yourself using free-as-in-beer Xilinx tools to perform any function you want (that fits in the CPLD). Board is GBP 2.60 plus shipping or GBP 10 plus shipping for the whole kit.
The article misses one of the most capable io expansion card. http://roboteq.com/i-o-expansion-cards/rio-smart-io-expansion-card-for-raspberry-pi
Demo video at http://youtu.be/cFqNjndLtqg
And the kickstarter project that made it happen http://www.kickstarter.com/projects/95547492/smart-io-expansion-card-for-raspberry-pi
IT would be an entertaining activity to build a stand alone data acquisition system. Use the tank as a motor, Battery, attach a robotic arm, and have the Gertboard ready to measure stuff. It could walk around and pick up soil samples, test them, send the data wirelessly, and move on...
the easiest option is to use a rear view mirror screen which takes UHF video from the PI. You can get these through eBay for $30 or so and take very little work to connect to the Pi (and no software). You can then tweak the Pi video settings to perfect the alignment to the screen. This gets you VGA level graphics. The only pain is these are designed for 12V (to be run from a car's power system) but some variants actually are 5v inside and with some bravery you may be able to steal that from the Pi connectors too.
This really reminds me of the days of the Apple II, Kim, IBM PC, and others. People were doing interesting things with computers that provided them the control that they wanted over their tech. The only difference is that the last generation is not saying silly things about how these computers are too small to be useful.
I see this generation creating a new set of technology building blocks that are going to challenge the Microsofts, Apples, and Googles to keep up. You don't like what they are offering? Build your own version the way that you want it. 3D print the mechanicals and assemble your own control systems for it. Computers used to be mysterious boxes, but now they are familiar technology. Embedded systems used to be mysterious as well, but the free tools now are better than what we paid a lot for not long ago and the technology is much more accessible. I've got to wonder what the next wave will be like...