I love the way the iphone scrolls through long lists, say contacts, by letter by touching the far right side of the screen and pulling up an "alphabet scroll" function, where you can quickly scroll up and down the alphabet to jump to a certain letter.
Seems it might be adaptable for an onscreen navigation via remote, making a nice and pretty way to scroll more quickly. Something like while in library view title mode (for example) with your huge movies list, pressing a "right" directional arrow on the remote shows the alphabet scroll bar on the right side of the library window, using up and down to quickly jump around the alphabet, then left on the remote to go back to the normal library window to navigate as usual.
I think this would require a bit more programming than is possible through the skinning engine, but I've only just started mucking around with it. Before a dev sees this post and responds with "sounds good - be glad to see your patch for it!" let me just state that I don't have anything like the time to actually figure out the coding. Besides I'd have to start nearly from the ground up in C/C++ unless this is possible through Python scripting, which I'm much more comfortable with.
Just mentioning the idea in case there is some coding wiz out there with nothing better to do and an interest in this. Yeah, I know!