The VIA APC is a tiny computer with an 800 MHz ARM processor, 512MB of RAM, and 2GB of storage. It includes HDMI, VGA, USB, and Ethernet ports and sells for $60 at Newegg (with free shipping).
One thing it doesn’t include is a case. Like the Raspberry Pi and CubieBoard, the APC is sold as a developer board, which means the motherboard is exposed to the elements.
But there are some third party cases available for folks that don’t want to build their own.
One of the nicest looking options I’ve seen is Mike Thompson’s laser-cut plastic case. It’s custom designed for the APC, holds the board in place, and includes cut outs for the I/O ports.
It’s also designed for easy assembly. It snaps together and doesn’t require any glue, screws, or fasteners.
Thompson is selling the case for $20 and charging $5 for shipping. Unfortunately the store front is down at the moment, but you can read more about the project at the APC forum.
This thing is a variant of mini-ITX so there are other case options. Just not quite as small as this board or custom case. But I wouldn’t pit this one on my TV either.
On the other hand the other devel boards, like the Pi, are totally oddball and some thought to a case standard is probably in order soon if the ARM system board market is going to develop beyond toys for uber-geeks.
I personally don’t find these products to be relevant anymore when you consider what you can get for $60 that is way more powerful than this (MK808) plus it is already covered. For the money you might as well just get one of those they already have cases to.
Most devices like this are intended for the embedded or education markets and not for general consumers to have a mini-pc or entertainment center device.
Mind that features like Ethernet and VGA ports are lacking in many of those more powerful devices you mentioned and this board also has more USB 2.0 ports with a total of 4 full size ports.