I've only run across maybe three Log Horizon fics in total, only one of which wasn't a one-off. Fortunately, that one was by Vathara; unfortunately for your purposes, it wasn't a crossover. (It also hasn't been updated since April.)
It's on FFnet and also on AO3, if you're interested and haven't seen it already.
Since I'm posting anyway: I've got a few things I'm wanting to write up to post that aren't exactly "should be", necessarily, but are more crossover-fic ideas I've had that I would like to see done but am unlikely to be able to do - and in any case would like to share. There hasn't been much of that in the CTSB threads, compared to the sort of thing that's been posted in the Non-Crossovers that Should Be thread; would it be considered appropriate here, or should I post such things separately if at all?
It's on FFnet and also on AO3, if you're interested and haven't seen it already.
Since I'm posting anyway: I've got a few things I'm wanting to write up to post that aren't exactly "should be", necessarily, but are more crossover-fic ideas I've had that I would like to see done but am unlikely to be able to do - and in any case would like to share. There hasn't been much of that in the CTSB threads, compared to the sort of thing that's been posted in the Non-Crossovers that Should Be thread; would it be considered appropriate here, or should I post such things separately if at all?