I'm finding that I tend to bump the left shoulder button from time to time while I'm reading, which obviously switches my view to the previous/next page (depending on my "option swapshoulder="setting). An option that allows me to disable the shoulder buttons would be handy.
Alternatively, since the DS only has 12 input buttons and DSLibris only has 6 distinct functions while in reading mode, how about adding options that allow custom mapping of functions to buttons? These could be used to override the button's "standard" behaviour.
<button name=LeftShoulder function=DISABLED>
<button name=X function=PREVBOOKMARK>
<button name=B function=NEXTBOOKMARK>
PS - I made my donation today, you've made an excellent product. I'm inspired enough to try some DS development of my own. :-)