Jinny Beyer has a book on color (Jinny Beyer's color confidence for quilters), which provides two pullout versions of color wheels on cardboard. She recommends learning to blend shades so that you get a seamless continuum of color between any two hues. I have never quite grasped her idea of blending. On the color wheel, the primary colors are bridged by the combination colors they create (blue to blue green to green to yellow green to yellow, etc.), and I can easily see how blues bend into blue greens, into greens, into yellow greens, etc.), but I don't quite get how she blends yellow directly into purple. Maybe your library would have a copy of the book.
Color wheels often have concentric rings, with the pure hues on the outside, the next ring being grayed colors, and the inner ring being very dark shades. I think it would be more difficult to make a wheel that didn't segregate the intensities this way.