I like the infinite scroll idea a lot. The whole "get to the end of a chapter and jump to the next" (similar to jumping pages in some PDF viewers) is unnatural and one of my dislikes about Rapier.

ARJWright, it looks like you've really thought about how to adapt to a small touchscreen. It would be great if core functions like "go to chapter & verse" and "read" and maybe even "word search" could be done just with finger input. Re: your buttons like "Commentary" and "Maps", I would vote for having this functionality accessible in some kind of pop-up to save precious screenspace for the text.