I noticed in the last month or two that streetview has been added for several regional cities and towns. Places with streetview that I don't think had it before include Saijo, Ehime; Masuda, Shimane; and Tsuyama, Okayama. I checked a few other somewhat out-of-the-way places randomly, and there's now good coverage in Nikko, Aizu-Wakamatsu, Otaru, and Tokushima.