For me, a 4" .357 revolver isn't hard to carry at all with a good holster and gun belt. As for the revolver, I'd look for a medium frame version, specifically a S&W K Frame or Ruger Six Series. Neither are in production these days, so you'll have to search Pawn Shops, Gun Shows, Gunbroker, classifieds, etc. These guns are ideal for carry because they have full sized grip frames and 4" barrels without the bloated flabiness of today's models like the S&W L Frame and Ruger GP.
I will say though, for a more inexpensive 4", you might look at the Taurus 66 series. I have a 66B4 .357 7rnd and have been nothing but pleased with it. I really guess I just got lucky with this one.
Good suggestion as well. Unlike some Taurus models that seem to be more problematic, their 66 (and older 669s) are generally very highly regarded. I regret selling my 6" 66 5 years ago. If it passes inspection, a 4" Taurus 66 or 669 would be a good option.
Here are some viable candidates with 4" barrels in .357 Magnum:
Rugers
Security Six: Adj sights, square butt frame
Police Service Six: fixed sights, square butt
Speed Six: fixed sights, round butt (actually not sure if these came in 4" or not)
S&W K Frames
Model 13: blued, fixed sights
Model 19: blued, adj sights
Model 65: stainless, fixed sights
Model 66: stainless, adj sights
The S&Ws will generally be a bit more refined with slicker triggers, while the Rugers are more durable (a good choice for shooting a lot of .357). The K Frames will do fine with 158 grain magnums, but stay away from hot mags under about 135 grains.
Here's a few pics to give you some ideas:
Ruger Police Service Six
S&W Model 13, 3" (also made in 4")
S&W Model 19
S&W Model 66 (2.5", also made in 4")