The 12" Chromebook models (Pixel Slate, Pixelbook, Samsung Chromebook Pro) are not any larger than the 11" MBA. They're narrower and slightly taller. The MBA just has enormous bezels and also a different aspect ratio.
Thanks, I haven't had a chance to try them out because the few Google products I'm actually interested are apparently only for the US marked. I'll look at some comparison pictures and make up my mind.