Yellow Zucchini

I don't know why we don't have yellow zucchini in America, at least not that I had ever seen. We have yellow crookneck squash, of course, and at Whole Foods there are all kinds of things like lemon squash and zebra squash and those half-yellow, half-green zucchini that look like they were dipped in paint. But I'd never seen the simple, speckled yellow zucchini (with its green cap, always!) until moving to Tokyo. They taste just the same as the ordinary green kind, but they certainly look better - they don't turn nearly as drab a color when cooked, and retain their pretty speckledness. And like all Japanese zucchini, the real mystery about them is why they cost a minimum of 100 yen each. American gardeners are overrun with zucchini and give them away - so why not in Japan?