This upcoming line of modular interface devices from Machine Collective look useful -
Machinecollective understands your needs and we’re here to help you out! We are working on a range of modules based on frequently used components, sensors and indicators. The prototyping modules are designed to work with development platforms such as Arduino and Wiring. The modules can also be used for other purposes such as circuitbending, DIY synths, analog sequencers or plain old electronics projects.
Developed for use with Arduino, Wiring and other platforms, the hardware is planned for open source release – Machine Collective