While the Pentagon is looking at RFID implants for tracking soldiers' physiological parameters, Senate Democrats are backpedaling on a push to ban e-voting machines without paper trails for the '08 election. There's a bit of a disconnect there, unless you realize that an electoral system only has to look good enough for there not to be a legitimacy crisis, and apparently the US public still hasn't quite grasped how much e-voting machines suck; military organizations succeed or fail on their logistics - of men, material, and information.
I'm not very concerned about the privacy implications, given the facts of military life. I'd say that being ordered to jump into a firefight is as dangerous to body integrity as being ordered to insert a chip under your skin, and data self-ownership in a military context is almost a paradoxical idea. An estimated five years before human testing does seem a bit too long, though, considering the current state of the art.