If you want to dump an insane amount of money into this, there's always the Pentax 645nii and 67ii

Both are professional level, full featured cameras with price tags to match. Anything affordable will be fully manual, but just like with 35mm cameras, you will find a whole spectrum -- from the Moskva 5 Russian Rangefinger to the Hasselblad H1 (aka what I want for my birthday LOL).