QUOTE (Bull @ Aug 8 2008, 11:46 AM) 
Damn shame more folks don't think like that. Here, have +1 Karma. 
Trust me, he tends to get +1 karma. He's one of the players in a game I run.
On regards to the datajack-arm-issue. If someone chopped off their arm and used a datajack to rig a robotic arm up I would treat it as a drone strapped to your body. You could use a simple action to issue the arm a command. If you want to control it directly you'd have to "jump into" the arm, paralyzing your body to control the arm. If you rewired the thing to take commands fluidly from your brain as if it were your arm, then it would become an unnatural extension of your body and thus cost essence.
Also the panda has pointed out to me that those buckles and straps holding the arm-drone to your stump would probably give out under less then impressive stress. Not to mention it'd probably be sweaty itchy and the source of unpleasent sores.
"NRRRRRRGH!" *POP* "Oh drek, not again. Could someone pick up my arms and give me a hand strapping them back on."
Besides, why strap an arm to your stump when you can have a chainsaw?