I do want to plan an upgrade tier for the Kickstarter! I'm not sure how to make that work with Kickstarter's infastructure, but I do plan to make that happen.
I'm currently managing another Kickstarter right now, so the best I can give for a timeframe is "When Spindlewheel is shipped". Cody and I have bounced ideas back and forth on when would work best, and our current roadmap places in spring of next year. But that's about as close as we can get.
This one PDF will get completely updated with the Kickstarter stuff too! The editing, art, and all that!