While scouring Google for more info on fundoshi, I stumbled across another blog, Nippon Boys, that has a strong focus on fundoshi. The blog author has chosen to make it an adult blog, since there is some male frontal nudity and more of a focus on the Asian male physique than on just fundoshi alone, however it is pretty infrequent and the majority of it is tasteful (regardless of how NSFW anything pertaining to fundoshi probably is.)
What struck me about Nippon Boys was the quality and variety of photographs that are posted: many vintage photos from the Japanese army, divers and fishermen, modern shots of college akafun swims, and what look like scans from magazines (that I would love to see more of!) I've re-posted a couple here so you can get a taste of what's in store, after the jump!
Nippon Boys was actively publishing between April and May of this year -- there haven't been any new posts since then. However, if you are of legal age and want to become a follower of that blog, it might encourage the author to post more from their obvious goldmine of fundoshi photos! I'm hesitant to post the link to an "adult" site on Fundoshi 4 All!, but you can find it by searching "nippon boys" under blogs, it should be the first site that comes up.
There's no way to leave comments on their posts or contact the author, but we obviously have a kindred spirit and fundoshi-lover at Nippon Boys!