At the moment, no, you can't have MobileSheets crop the bottom of the last page to remove whitespace. That would be a feature I would need to add, and it would only really make sense for the vertical scrolling display mode when using ChordPro or .abc files. I'm not opposed to supporting this though, as I can see the value in it. If you need an even slower scroll speed, you can tie it to the metronome tempo, and just use a really low tempo if you don't need the metronome.
Mike
Mike