Huge disclaimer: I've never used the iPhone app, so if something like this has already been implemented, please forgive my ignorance.
With that background, it may seem to make little sense as to why I would be making a suggestion regarding the iPad app, but here's the deal:
I was sitting in church this morning, using library.logos.com on my Blackberry 8830 to follow the sermon. This is currently my only avenue for mobile Logos access until the iPad comes out (and until I save up to purchase one.) Aaaanyway, I found that the biggest obstacle to using my Blackberry as my primary Bible in church was the navigation of the Bible as the pastor had us turn to various passages and cross-references. While bouncing around in a paper Bible is trivial, I found it to be very cumbersome on the Blackberry (navigate back up to the passage box, enter the new passage on the keypad, wait for the passage to load, by which time the pastor is almost done reading the passage from his paper Bible.)
So I was thinking that I sure hope that navigation would be better once I get an iPad. I was thinking of two different navigation methods, either one of which could/should rival the speed of competently navigating a paper Bible:
1) Having some sort of "tab system" down the side (similar to Bible tabs [which I don't use on a paper Bible, but would make sense on an electronic one since you can't intuitively "flip" to the right place in the Bible]) that would allow you to "swipe" to flip to another book and then another chapter in the Bible. I imagine this wouldn't work on the iPhone due to space limitations, but I would think the bigger screen of the iPad would be able to accommodate a system like this.
2) Having a "navigate" button always visible in the upper-right corner (or wherever) that, when clicked, would show a full screen of buttons...one for each book of the Bible...that would operate in a "drill down" fashion. In other words, if you clicked on Genesis, the books of the Bible buttons would be replaced with 50 numbered buttons...one for each chapter in Genesis. With this method, three button presses would take you to the book and chapter you are wanting to navigate to. If the navigation needed to be more specific than that, I suppose you could add another layer to the drill down that is either divided by pericope or verse...but I would think that 95% of the time drill down to chapter would be adequate.
Again, if a really quick and simple navigation system has already been implemented in the iPhone (and soon to be iPad) app, then please forgive my ignorance. If not, and if you like one of my ideas, you can thank me with a free iPad. (Just kidding [:P] LOL)
What do you guys think?