I have been developing an accessory board for the R-Pi to provide 8 high level outputs (1/2 amp 28vdc) and 8 impedance protected digital inputs. It is called OctaPi and uses 4 GPIO pins. The board includes a buffer for the GPIO and a universal power supply to provide 5 VDC for the Pi via a USB plug. The I/O have LED status indicators included. It will come with a connector kit including a decent industrial type header connector for the GPIO, not the typical and unreliable mass connection ribbon cable. OctaPi is designed to be expandable in further blocks of 8 in 8 out, without needing further GPIO resources. The connectors are 1/4 " quick slides that are readily available at retail level, although the connector kit will include them. We are hoping to have production units ready by the end of 2012 for on-line sale. A single python function call updates the outputs and returns a list of current input status. Here is a link to the newly created (and under construction) Facebook page. OctaPi is designed and will be made in Ontario Canada. Price to be announced shortly.