I bought a package of NutriKitchen soybean pasta at my local store (Berkeley Bowl), more out of curiosity than anything else.
It is 100% organic soybean; not soy protein, not tofu.
Unexpectedly it turns out to be delicious. It is cvalled "angel-hair" style, but is more like spaghetti. Cooks in 3 minutes (quite al-dente). Obviously it is wheat-free, high protein, high fiber.
It has a delcious rich "meaty" taste on its own, although we immediately doused it with a superb toasted walnut/ parsley pesto with lots of cheese and garlic.
The store only had the "golden" variety, though I see on the web site there are "black" and "green" varieties.
It cost about $3 for a package (serves 4) and it is made in China. Worth trying, even if you are not on a special diet.