It came to me in a dream: while the black & white warp is still alive, why not weave those black & white double plain samples you've been mulling over? Yes, double plain weave.
The calligraphy brush in Photoshop seems to have made squiggles that look like two-legged llamas. So be it.
Two of them turn out to be doubles, so there are eight tones in all. Hm-m-m.