I wanna start shooting medium format (120) black and white, mostly because of quality of grain and sharpness

however I'm really married to the style of photography that comes with a 35mm SLR camera. realistically, are there any decent 120 cameras that would be more like a 35mm SLR?
I'm talking in terms of size, weight, portability, being able to handhold it and use an internal meter. in other words, being able to take a spontaneous shot "somewhat" quickly. i almost always shoot in manual