It looks like Windows Phone 7 (WP7) devices will soon be getting different resolutions, but they will still be limited to a list pre-defined by Microsoft. While Microsoft has taken a lot of measures to ensure that the WP7 ecosystem is consistent, better resolutions will help sell more WP7 devices. Fortunately, the XAML model seems to scale up very well, and I do not think that larger resolutions will cause applications to look bad.