We just made Mistral Medium available as an Experimental model on Sudowrite.
With decent smarts (reportedly edging out GPT 3.5 Turbo) at a modest cost, Mistral Medium falls in the Goldilocks zone of models. It's a more permissive model too, less censored than models from Anthropic and OpenAI by default, and also natively fluent in multiple languages (including English, Spanish, French, German, and Italian).
You can find and select it in the Experimental section of either your Write Settings' Prose Mode dropdown, or the Chapter Generator dropdown. It's also available as an option when building an Advanced Plugin, in the Engine dropdown (under AI Options).
Give it a whirl, and let us know where it works best for you!