Balloon is an Open Hardware board, designed for embedding into projects needed low-power, high-performance poartable computing. It can be built in various configurations, with either FPGA for maximum welly, or CPLD for minimising power consumption. It is based around the Xscale 270.
The project has its origins with some of the people involved with making LARTs, and Balloon2 saw the light of day in in 2003, and over 5000 have been made.
Balloon3 has had a long gestation with enormous support from Cambridge University Engineering Dept. It is now available, and has a company (iEndian) formed around it which is running production, sales and support.
Specs are available on the iEndian site or on the Balloonboard Wiki.