There is no one-size-fits-all design solution for the Bible. In addition to being the "bestselling book of all time," the Bible is also one of the most complex design challenges. One of the things I advocate for at the Bible Design and Binding Blog is a single-column text setting. But I'll be the first to admit that this isn't a panacea. Some people are going to prefer the traditional double-column design, and that's fine. I would never argue that double-columns should disappear -- I'd just like the other option to be more readily available.
The thing is, Bibles are set in two columns for a reason. Because the Bible is so big, the text tends to be small, and stretching a line of 6 pt. type across a 6 x 9 inch page isn't a recipe for readability. With two columns, a designer can fit more words on the page, and the individual columns can still be proportioned for easy scanning.
To make a single-column setting work requires more than just waving my design wand and converting one column into two.
If the page size remains the same -- let's stick with 6 x 9 -- then I'll have to make the type larger, approximating the size of type in your average trade paperback. Jumping from 6 or 7 pt. type to the region of 12 pt. is going to mean fewer words on the page, and thus more pages. Another option: keep the type small, but leave huge margins. Imagine a two column layout where one disappears and the other increases to about one and a half times its previous width, with an ample margin on the side. That's a lot of white space, though, so I can put notes and references there to balance the page.
The most obvious solution, though, is the decrease the size of the page, so that it's proportioned with the ideal text column in mind. I'll suggest that something like 4.75 x 6.5 is optimum. That's the measurement of Oxford's combined NRSV and Book of Common Prayer, a volume the feels good in the hand is seems perfectly proportioned for a single column of text. (In fact, the Prayer Book section is set this way, and looks perfect.) Of course, shrinking the size of the page is going to increase the number of pages -- just as bumping up the type size would. Again, the combined Bible/Prayer Book seems like a Golden Rule. Mine measures about 1.75 inches thick. Too fat? Not if you ask me. I prefer small and thick to big and thin.
This is a subject I'll try to flesh out over the next few weeks, so I'm creating a new category of posts called The Perfect Format. The title is not to be taken too seriously. As I said, there is no one format that's going to work for every application. But I'm hoping to illustrate what the perfect format would look like for me. Stay tuned.