Thanks for the suggestion. Not bad overall, but a little different from what I'm trying to find. There wasn't really any true NTR that I could find; NTR implies that not only does the hero's crush/love get taken from him (hence the -torare), but that he finds out in a very unpleasant manner, not by being told that she's been taken, but rather by seeing for himself. Occasionally he might just see her blushing and cuddling with a boy, like an event that one character recalled in the series NHK (though not everyone would call that true netorare), but usually it's a lot more severe and graphic, effectively slapping him in the face with the fact that she's with someone, or that she'll be with almost anyone except possibly him. In this case, he just found out that she'd started going out with the guy the day after it happens, nothing more than verbal acknowledgement, not to mention that she is not the single central and ultimate love interest. I'm looking for something where the obviously unrequited love does eventually get through, and she returns his love completely.
One possibility is something that a few people on other anime sites said about alternate setups for B Gata H Kei, before people saw enough to start liking it: one suggestion was that a guy like a girl and find out that she is what Yamada wants to become (a total, absolute tramp), thus becoming very uncertain about pursuing a relationship, while at the same time the tramp finds herself falling for him and wanting to "settle down" as it were.
On the lowest level I want stuff where he knows her heart cannot be his, suffers and perhaps surrenders to the loss, but at some point, things change. Things taken for granted are noticed, hidden feelings emerge, new feelings blossom, and she loves him. The things is that I've seen all this stuff where the situation is made much more intense, shocking, and painful by the hero's finding out his loss in the worst way possible, so I want stuff where this is part of it, where he does get crushed by a sight that no one should have to see, but even so eventually she turns to him.
Also, I'd like a hero who's a little more likable. It's okay for the guy to be cruel when his heart's broken, but I want to be in a position where I feel that the guy deserves to find love and that it really is wrong that he lost out. Kurosawa eventually becomes like that, but it takes a while and for a long time he's a moster, not to mention that the story is mostly about his return to humanity rather than his finding love. Again I'll say that this was good, very good, and had some great stuff at certain points, thank you for the suggestion. Just not quite what I was aiming for here. Perhaps a little less drama, or at least less widespread atrocity, and a little more romance and focus on the ultimate pair.
Edit: After looking through my old stuff, I found one series that is very close to the sort of thing I'm looking for: Momoiro Peanuts by Tsutomu Mutsuki. Be forewarned, this does contained well-censored H and pseudo-loli, and only 3 chapters have been translated, though the serious stuff is several chapters further along. By pseudo(fake)-loli, I mean that the central girl is implied to be 18 and confirmed to be no younger (at one point a particularly perverted character jumps on her with the thought "Over 18!? OK!!"), though she could pass for 9 easily. I'm not particularly adept at Japanese and Kanji, so I'm not sure of everything, but here's what I can make out:
Spoiler for Momoiro Peanuts plot:
The leading girl is in college and is now residing in an apartment or dorm with several others. In high school, a seemingly perfect guy charmed her and began dating her. He was kind and gentle until they'd been having sex for a while, after which he dumped her without a second thought. Somehow, I believe this led to her developing a second personality, one that comes very close to being a "succubus". She occasionally blacks out and becomes desperate for sex. Eventually, she even does it with the manager's brother, who's about the same chronological and apparent age as her. They'd started to get along well, but this changed things. When he learned about her "condition", he avoided her for a bit while he tried to figure out just what it meant and how he should act; this reminded her of her past, and she thought that he was another man who for some reason abandoned her once he'd had sex. Since only his older brother had never changed toward her regardless of sex, she went to him in desperation. How much the younger brother heard isn't clear, but he heard enough. Before he'd been able to figure things out, she'd been taken away. They dated for a while, though the girl really was merely comforted by his unchanged acceptance; eventually she realized that he was in love with someone else who he thought was unreachable, and broke it off with him. Though free again, her relationship with the younger brother remained bad, though true to tsundere style, her real feelings for him were far from what she showed. Eventually, she couldn't ignore what she felt, but couldn't tell whether she was in love, so she attempted some "intimacy" to find out. At first she still doesn't accept her feelings and just loses herself in the act, but after the boy tells her that without heart it's no more satisfying than doing it on his own, confesses clearly to her and challenges her about how she feels, everything changes. She can tell that he's inexperienced and clumsy, but still she finds that it's like nothing she'd ever experienced before, and she's flooded with sensations and emotions completely alien to her. She finally accepts her love and starts anew.