Looking at Ballistics by the Inch, I note that the Federal 240grn Hydra-Shok was doing 1120fps from a S&W 629 with a 3" barrel for 668ft. lbs. While certainly not up to par with a .44 Magnum from a longer barrel, that's still more power than what you'd get from a comparable .357 Magnum loading out of anything but a 6" or longer barrel. Federal Hydra-Shoks are not a particularly hot loading in .44 Magnum and I suspect that something like Speer's 240grn Gold Dot would give substantially more oomph.
As far as my choice of a .44 Magnum, I'm partial to a S&W M29 or 629 with a 4" heavy barrel. Regardless of the weight, an N-Frame is just too big to be a pocket gun and, since I've yet to find anything that is remotely comfortable for me to carry IWB, that relegates it to a belt gun anyway. A 4" barrel is small enough that I can carry it without undue discomfort under a light jacket but I've still got a longer sight radius and higher velocities than what a shorter barrel can offer. I like the weight of an N-Frame with a 4" heavy barrel because it's light enough to be carried all day with a good holster and belt (I use a Kramer horsehide scabbard and a 1 3/4" wide Bullhide belt) but has enough weight to get through a 50 round practice session without becoming unpleasant.