I recently discovered this forum and think it’s a great idea. I was looking forward to see what all things are already there in this space when I stumbled upon some projects that I could use. Following is a dump of the things  I am going to use/ and some other ideas :

1. This community
2. A hackaday project : https://hackaday.io/project/3800-3d-printable-robot-arm by Andreas Hoelldorfer (have pinged him, haven’t yet received a response.Will update)
   The most amazing part is the ‘3D printability’ of this project. All you need is something like a Delta with a large enough print volume. Also like the fact that there is a DC motor version and a stepper version.
3. Yale Open Hand Project (http://www.eng.yale.edu/grablab/openhand/#hands)
4. Linux and ROS : Both are open and are a perfect fit for such a project. A robotic arm is potentially doable using a uC but having Linux onboard makes it so much more fun.
5. Beaglebone Black : OSHW, great community and documentation, more than enough pins, runs ROS. Also, this will most likely be compatible with the soon-to-be-launched Beagleboard X15.
   A modular system using capes/capemgr will work wonders. So for example, if I switch in between the different Open Arms, all I have to do is load a different cape and everything else will fall in place.
6. Price needs to be in the extremely affordable range. So something around the $300 mark including the electronics, motors, etc.
7. Other generic tools like GitHub, Hackaday, Wikis.
8. I also need a cool name for this project 😀 !