1. Goukou x Kaiei
-original dragons incest. Atavistically possessed Goukou forces his attentions on accommodating 'fine with that' oldest son, followed by complete happiness on both sides.
2. Aoarashi x Ritsu
-100 Demons BTN yaoi in which pointy-ears!Aoarashi is Any Kewl Angsty Demon Rapist ('Your grandfather made me his possession. Now I make you mine. Bwahaha!/ Why do mortals die so soon? Ohhh Kagyuu-- Come baaaack to me!') and Ritsu is Oh god why me/ oh jeezus these youkai/ fine, fine, 'Here I am, do as you please.' (Marriage of Figaro, "Io son qui, fate quel che volete." You are to hear that line as sung by Kiri te Kanawa BTW.)
Followed possibly by Aoarashi's So uhh where does it go? Ritsu: Look, this was *your* idea. *You* figure out where it goes.
3. Aoarashi x Kai
-as suggested by mvrdrk. Kai the wannabe onmyouji is always dropping heavy remarks to Ritsu about getting a piece (literally) of Aoarashi, his father's strongest shikigami who got split into four a while ago. (Carrots in ears Kai somehow can't grasp that Aoarashi isn't Ritsu's to give or take as he pleases. 'Just one piece, one liiiitle tiny piece, aww c'mon?') Kai takes matters into his own hands and goes after Aoarashi directly. Annoyed Aoarashi, who's always had a low opinion of Kai anyway, turns tables and gets a piece of Kai. Comedy. More comic if Aoarashi is in human form cause ya know, that body is probably younger than Kai is now.
4. Kai /Akama
-because Kai isn't a total jerk and is, in fact, better at onmyouji-ing than Ritsu, who I believe never tries very hard to be one. Hell, even Akira in her amateur way is better at onmyouji-ing than Ritsu. Both Kai and Akama have very good opinions of themselves au fond, though I'm seeing the effect of Kai having walked into a house at 21 and left after the weekend to find he's 46. The best part of adulthood, the time when you set up the conditions that let you live in the declining years- marriage, work, kids- gone like *that*. What's he got left but what he always wanted, which is mastery over youkai? and if it costs him years off his life, well, he's already lost so many of those a few more won't matter. A confrontation between Akama, the youkai with too much time on his hands and an itchy compulsive interest in humans, and Kai, the human with not enough time and an itchy compulsive interest in youkai, might be interesting. Also I'd like to see Akama pwned by a clever someone who does it consciously, as opposed to Tsukasa's selective vision technique: 'Ak, a cockroach! WHAP!!'
5. Waki x Konoe (or is it Konoe x Waki?)
-Ze comfort fic. Because shikigami makers need love too, and Konoe's the only one thoughtful enough to provide it. If Waki is angsting over Kon's original, or some kami who resembled Kon, whichever, tall manly bad-mouthing kami won't quite fit the bill, but hey- paper is an adaptable medium. And Konoe *thinks*, which sets him apart from the other kami.