I appreciate the efforts that have gone in to making the wonderfully clear interface and that HTML is the easiest way to display it, however, on an iPhone4 the interface is awfully cramped! Especially given that the url bar is always present in portrait orientation. In landscape it isn't too bad as the bar isn't displayed.
Perhaps an app would be better for these devices as that would give you the entire screen to play with and to also use side-swiping to different pages, such as track progress page, album art page and volume page!
The downside is you'd have two more code bases to maintain!