Sorry about this, but confusion reigns here!!
What's the difference between working on Longhorn in a COM environment, and writing a "Longhorn-specific" application?
My understanding is that some of the project names you mention, such as Avalon are critical in that they are the user-interface to Longhorn. Are you therefore saying that I can write a VFP application on Longhorn, but I can't make it look like an app written in C# for example? Are applications that do not take advantage of the Yukon/WinFS new disk system going to have to use a thunking layer and therefore run slower?
Sorry about all these questions.
Simon