For some reason, I want to build several versions with small differences, i.e. different application icons for different customers. For example, icon1 for customer 1, and icon2 for customer 2.
On Visual Studio 2010 UI, you can only the one icon for all configurations. But when you open .csproj file as plain text, you can see it's real powerful. All per configuration settings are under tag like this:
So just find images\AppIcon.ico that doesn't belong to your configuration, and add it to the configuration you want. All done!