http://www.youtube.com/watch?v=0C0dmGeE4MI

http://en.wikipedia.org/wiki/FN_P90

This “selective fire personal defense weapon”, or “submachine gun”, or “compact assault rifle” has been around for 20 years, and I just noticed it.  It comes with longer and shorter barrels, has little or no “climb” when fired even on auto, and a 50 round magazine which doesn’t stick out all over the place.  The “bullpup” design gives it a relatively long barrel in a short space.

If the utmost in concealability is not needed, this is what I’d want in an up-close firefight.  The 50 round magazine and ease of handling would be the determinants for me.