Check out this video. Drone technology is well on it's way to Shadowrun levels.

For some reason, when I tried to build a robot in my advanced science courses in High School, it didn't play well with others...

https://www.youtube.com/watch?v=YQIMGV5vtd4

The latest incarnation. Note how they sound like a angry group of wasps...

Btw, here is a new clever trick in their arsenal:
https://www.youtube.com/watch?v=VIkqqVr_u9U

I can foresee it packing a SMG and being able to have it on top of bottom depending on the available cover...

I'd rather put it on the bottom (or at least below the rotors) to keept the thing balanced. The best way would probably be to mount it in line wwioth the thing's center of mass - that way recoil will push it in line rather than sending it in a roll and spreading the bullets all over the place.

As always the jap mega corps have there own version

http://www.youtube.com/watch?v=ndRxU1wRIYM

For all the fans of snow crash, the rat thing version 1.0 has been developed

http://www.bbc.co.uk/news/technology-17269535