I agree, if you use Tri-X, a medium format camera, and most any developer (D76 would be my choice), there you are. Smooth tonality. T-Max would be smoother, but not my film of choice. 4x5 would give even creamier images.
Or, you could use C-41 B&W in a 35mm camera. Nice and smooth, and easier than toting a MF camera. I love the tonality of Tri-X and 120 film, but I do not like the large cameras that go along w/ that, which is why I went back to 35mm. MF is a whole 'nother style of shooting style, and I prefer the quickness and ease of 35mm. Still, if you want smooth film tones in B&W, that's a good way to go.
Also, and this should be obvious, beware of making any decisions based on someone's online images. You have no idea what sort of post processing was done to achieve what you see on a monitor. I can run some rough looking B&W scans through noise reducing software and get a totally different look w/ just a few mouse clicks.