We've had this requested many times and we're happy to say work on this feature is underway and will make its way into Studiometry 9.0. You will be able to create an unlimited number of custom pages (instead of just two), you can choose any one page as your "repeating" page to ensure all items appear on your invoices (instead of it always being the second page), and you can mark any number of pages as "always show" to include as many pages of terms and conditions as you'd like.
Studiometry will also calculate pages intelligently, so if you want, for example, an introductory cover page, several "items" pages, and then finally a totals, page, your items will be spread out correctly between the pages. More info soon, and we'll be opening beta testing some time this summer.