Combine it with this, http://www.youtube.com/watch?v=BCPQTAm_rlc Or simply the predator drones.
No need. Just mass produce them so the unit cost is below $100 and put a little dollop of C4 in there for antipersonell use. Or for harder targets, maybe a self-forging copper disc warhead in it like the little anti-armor "smart skeet" that are similar to the ones in the BLU-108.
http://www.youtube.com/watch?v=AKdFCsycYm8The antipersonnel ones could home in on a combination of body heat, sweat ammonia, voice/speech recognition (enemy language), or even image/pattern matching on enemy uniforms or equipment. (Home in on a Kalashnikov vs an M4/AR etc...)
With facial recognition even in consumer portable electronics like cameras and PDA's. (the "smile" and face boxing/bracketing feature") it's not too far fetched to presume that individual facial matching might be possible. The perfect assassination tool.
If you've seen the other videos you've seen the "perch on a wall and wait" behavior these drones now have. Or the ability to vault through windows or hatches. So one could be flown up the side of a building a few days before an event, then make a dash for the podium at a rally or speech etc.