Calao, a French company that specializes in producing prototypes for industrial use have just made a complete Linux Computer that fits inside a USB key.
According to its website, Calao was founded this year by a group of embedded developers, with aim of providing micro/nano hardware products and designs technologies to OEMs (original equipment manufacturers) serving industrial markets.
Calao's USB-9260 USB key-sized SBC measures 3.3 x 1.4 inches (85 x 36 mm). It is based on an Atmel
AT91SAM9260 processor, an SoC (system-on-chip) powered by an ARM926EJ-S core clocked at 190MHz. The SoC targets "advanced applications such as GPS application processors," according to Atmel.
The tiny USB key SBC has 64MB of SDRAM and 256MB of NAND flash. I/O includes a USB 2.0 device port (obviously), a 10/100 Ethernet port, and a pair of USB 2.0 host ports. The device also has a 50-pin expansion interface, although the company has not published the pinout, nor announced any specific daughterboards.
http://linuxdevices.com/news/NS6730529835.html
That looks really impressive, and a tiny computer like that could be highly useful for industrial purposes!