I'm sure there're many places in central Honshu with nigoriyu, but the places I can think of for that (besides Sengokuhara area of Hakone) are Shirahone Onsen and Manza. Both are pretty out of the way from the Tokyo-Kyoto corridor. Zao Onsen's got some of that, too, but that's up north in Tohoku region.

Keep in mind, though, that you can have very high-quality silky-texture onsen that's completely transparent in color.