I know this is an old topic, but it's one of the reasons I was inspired to start working on this scene / GUI editor. There's still a few things to do before it's usable. I thought now might be a good time to start talking about it.
I built the editor for my own projects, but I've always had it in the back of my mind that the MonoGame community might benefit from something like this.
My goal is to figure out if this is something the MonoGame community might be interested in?
Also, in the not to distant future, I'd like to get a couple of volunteers to use the beta version and provide feedback about it. This will be a fairly informal process of emailing each other, or discussing it on the forums. We'll be trying to figure out how to best use it in actual games, and what features are most important.