What's the point of this? Xamarin is cross platform and a lot more "lightweight" than this will ever be. xamarin.forms supports mac, windows (uwp right now, wpf soon), GTK, Android and iOS.
Sure Xamarin.Forms will be a lot more "lightweight".
Chromely is an HTML desktop app.
All the options you mention will end up being traditional (with their own controls) desktop apps with HTML support. Chromely is pure HTML. Chromely is not tied to rigid frontend controls .. you can use any html/javascript/css framework you like.
Chromely does not use WinForm or WPF. Extendable to WinForms and WPF for those who want to.
