I have been looking for something like this in Go for a while. I think there's a real opportunity for Go to provide a great developer experience for cross platform UI due to how simple the build process is. Speaking from experience, half the pain of cross platform development is managing build complexity, which Go basically eliminates.

I'm curious how you'll end up solving for cross-platform layout when native controls have different intrinsic sizes per platform?

This is something I haven't seen solved super well in cross platform toolkits.

Wishing you luck though.