Not sure about a 4+2, but it was traditionally a 5+2 (or if you did research in residency 7+2). Obviously the '2' in this case is a seperate fellowship that you apply to as a PGY4 Gen Surg resident. These still exist.
Regarding integrated programs, my understanding is that there a few different models (3+2, 0+5 etc) usually with the first number being gen surg years.
Yes, but they aren't programs into which you match directly, nor were they ever. Wash U still has one, but you have to match into general surgery, then, for lack of a better term, "prove yourself" to get the spot.
University of Southern California has one. ACGME rules only allows residents who are currently in the General Surgery Program at the same institution to do the ESP program (4+2). Agreeing with the previous post.. its basically a prove yourself to the program kind of deal.