Windows Detour? Not So Fast…
"There's no Longhorn server family on tap, Microsoft says. But there might be a limited edition server timed around Longhorn client's release."

This must be some kind of press full-employment act. Obviously there will be an upgrade on the server side with the Yukon-dervied Windows file/future store is complete, circa Longhorn, even if they don't hire the Rolling Stones to launch it.