This is probably not what you are referring to, but the link will take you to some of the nicest cybernetic arms around. They are for V3 but will work on V4 too.

http://www.daz3d.com/i/3d-models/-/cyber-arm-for?item=3788&_m=d

Also, the bot armor has some excellent legs and arms you can add to V4. I don't know if they'll work on V3.

http://www.daz3d.com/i/3d-models/0/bot-armor?item=8101&cat=&_m=d

Good luck....