Hi Chris ! ,

Are you thinking of designing a teach pendant like kuka, nachi etc ? because its very usefull to programming robot..

The other question is Do you think about change arduino ? i think it is very slow to drive all motors at the same time 
 
I'm a big fun of you :) I'm working on to create my own robot and I benefit from your design, software and firmware.I will share all of things when I finish as you :)
 Thank you so so much your advice and to share your experiance..
  
  Best Regards!