Wait, that project actually got off the ground? Is this something you're using in production? What's a good starting point?

Not the comment you're replying to, but I also have a couple of internal winforms projects at work. They make it much easier to diagnose and debug issues with a backend service that works with GIS data, using libraries like GMap.NET. Come to think of it, the company's environment management tool is a Winforms application that gets used in every production instance. For basic UI tooling in a dotnet shop it's second to none.