I enjoy my Ruger SP101s and my J-frame 638 airweight, but you might do well to take a look at a Kimber K6S:
The 3" is the lightest production 6-shot .357 Magnum for their barrel length, if memory serves. Mine weighs the same as a 5-shot 3" SP101, but I have another round on tap, along with better sights (I was easily able to swap to 3-dot night sight front and rear due to dovetailed sights), better DAO trigger, and the dehorned shape at the rear means it doesn't poke me as bad IWB.
You definitely know you're touching off .357s with it, but this 3" with some three finger Hogues or the Comfort Core grip that wraps around the backstrap really help; far more comfortable than a 2" S&W 640 with .357. I wouldn't want to fire a .357 LCR or S&W scandium J frame; they might be lighter, but I want to practice with it.