I prefer to edit with the keyboard, so shortcuts like "Alt+Shift+E" to edit are valuable. In the Page: namespace used on Wikisources, we don't have shortcuts for navigating pages. I'd like to propose that we 1.) add these and 2.) that they should be "Alf+Shift+→", "Alf+Shift+←", and "Alf+Shift+↑", for navigating forwards one page, backwards one page, and to the index. Thoughts?
An alternate proposal made below is "Alf+Shift+>" and "Alf+Shift+<", to which I would add "Alf+Shift+^". On most QWERTY, Windows-style keyboards, these maps to the following keys: , . 6 (but since you are hitting "Shift" anyway, they would be the characters suggested by Billinghurst).