You have done an excellent job of enhancing the desktop experience in Windows 8 with Start8 and Modern Mix. I would like to suggest you consider building another type of application that I think would further enhance the desktop experience: a desktop notification center for metro apps.

I have started to use some metro apps (e.g. mail, calender) but I spend the vast majority of my time in the desktop. I don't think the notification methods in Windows 8 serve desktop users very well. You either have to notice a transient popup that appears for in the upper right of the screen, or you have to periodically go to the start screen to view live tile information. Personally, I would like a persistent indicator in the desktop taskbar letting me know if I have any notifications from metro apps, ideally with a number on the icon letting me know how many. Furthermore, it would be nice to be able to click this icon to show an expanded set of information - e.g. which apps currently have notifications.