To anyone interested - I intend to run a similar exchange in 2020 and possibly future years, with Crossovering's original conceit of matching on fandom combinations, and possibly media, but not on characters or relationships. It will be in between Jukebox (ends June) and Yuletide (begins Sept).

If other people want to run their own that's also cool!

I will reply to this comment with a link when I've settled on the exchange name and schedule.