Michael Erwin's R-Series Controller Set (Beta)
1 x Controller v7 (Mega Shield)
1 x Receiver v6 (Mega Shield)
3 x I2C Module v8 (UNO Shield)
2 x 24 SlipRing Interface v3
These are open hardware! http://code.google.com/p/rseries-open-control/ for designs and documentation.