In this mockup I've tried to answer the following questions:
How should selection be indicated?
How to display each slide's title using a rollover
How are new slides added?
Interactive features of this SWF:
Click on each thumbnail to show its selected state and to change the currently active slide.
Hover over each slide's thumbnail to see its title.
Move your cursor over the left edge of the thumbnail pane to display the Add Slide buttons. Clicking these would let you add new slides at any point in the stack. Buttons are present at the beginning and end of the stack and in the gaps between each thumbnail.
Hover over any of the Add Slide buttons to display a tool tip.