Hi there! A day ago I launched a bootstrap campaign on circuits.io in order to get funding for an open RPi Robotic Shield which I made. I now have a fully working prototype which fits on top of the RPi and is able to power the RPi, control two motors, two servos, provide 4 A/D channels and more.
With this module anyone can build his enhanced RPi robot. Currently I'm improving the module and if there is sufficient interest we will be able to sell these shields fully assembled for USD 49. If you are interested, take a look on my campaign page for the full specs!
I'm also interested in YOUR feedback about this module, if there is must-to-have functionality, I'll still be able to add it to the shield!