The game classic "Arcanum" (get it on GOG or Steam) has the best stealing system ever created. At night when the NPC is sleeping, walk into his/her shop and locate the shop-chest, but remember to not steal everything or the storekeeper is put out of business.
All the things you the player need to do to actually "steal" in Arcanum is amazing. And really beside the graphics by today's standard, the game beats most modern RPG's in story and technical RPG innovations. Troika Games... R.I.P
