FOLLOW-UP: It's been a day since I tooted this, and this has been boosted 53 times and favourited 44 times. So I guess there could be enough of interested people for this kind of instance to be viable.
But don't hold your breath yet! I'm working on it, but I'm famously slow to realize things. A polyglot instance will open at some point in the future, but for now I can't give any time frame for this.
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