Aletheia's

I think you and I may have talked already about this -- what *I*'d love to see is Rivers of London crossed over with Urban Magic, and also RoL with Dresdenverse
We have, and I think I would check out that, too. Especially if it had more Peter being curious than anyone else from RoL. :)

And I feel like Thomas/Justine would be hard to do justice
Exactly. It would be tricky, because as I see it, writing it half well would be writing it entirely bad. And written well, it would be a heavy piece and risky in a way. Very few writers can manage such sort of literature, especially if it's to be enjoyable on top of all... (Still, I do see such skill level once in a while in various fandoms, so it is possible and even relatively popular, even more than good plots, which don't really happen that often in fanfiction.) So, it's not like I even demand miracles from Butcher or blame him for not writing complex psychology in action genre; I'm just pissed when he makes a disaster even of this little he does write about these two.
Truth be told, some half a year ago I was this close to writing at least a fragment or two myself, until my better judgement caught up... I'd probably whip up something hardly better than oh-so-emo teen crap. :)

You mean I accidentally made up a meme? :D Every time I tried it deliberately, they went down like soggy paper baloons, so I wouldn't mind it at all. *g* And yes, the more prompted writing events in fandom, the better. (*cough* Says who never really participates beyond throwing prompts, but whatever.)